What is the English equivalent of 干物女 (dried fish woman)?

Literally meaning dried fish woman, the popular slang 干物女 is used to call a woman in her twenties or older who, as nicely summarized in Wikipedia, has many of the following traits:

メールの返事が極端に遅い、短い (Her text replies are very slow and short.)

簡単な食事なら台所で立って食べる (If it is something simple, she will eat it standing in her kitchen.)

忘れ物を靴を履いたまま、膝立ちで部屋に上がり取りに行く (She will go to take forgotten stuff in her flat on her knees keeping the outdoor shoes in the air rather than put them off.)

休日はノーメイクでノーブラ (She won't put on her makeup and bra on nonworking days.)

半年ほど美容室に行っていない (She won't visit a beauty salon for half a year.)

冬場は毛の処理を怠る、又はしない (In winter she won't shave or wax her body hair properly or at all.)

1人で居酒屋に入れる (She has no problem going to a pub alone.)

最近ドキドキしていない (She rarely gets so excited that she experiences an increased heartbeat.)

What is the English equivalent? In other words, how are such women commonly or idiomatically called in English?

UPDATE: Following a valuable comment below, I would like to explain the common pattern. These traits come together for a reason. There is a psychological root cause. It is a permanent psychological state of mind that manifests itself in many forms such as those described above. Psychology is not a rational thing, so it is hard to describe that state of mind in well-defined rational terms. But look at the literal meaning. It is a dried fish, not a lively fish. It is like psychologically giving up in the most global sense. A dried fish woman finds many things to be 面倒臭い (bothersome, tiresome) and, as a result, does not do them. I think that inside her brain, a dried fish woman gets decreased positive rewards for doing good things and/or increased negative feelings from having to make efforts. Such a shift results in a dried fish woman electing not to do many things many other women do, as described above. A dried fish woman does not make efforts to find a significant other. It is not a conscious decision to never marry, but rather that she lacks a motivation to make efforts or finds relationships to be bothersome. As a dried fish is devoid of moisture, a dried fish woman is devoid of energy, motivation, feeling of love, etc. "Lazy" is a somewhat close term, but is too generic. The term "dried fish woman" is about a certain way of life described above and caused by a specific state of mind as explained above.

Unfortunately, the best answer to your question is that, there is no single word or phrase for the kind of person defined by this idiom, which includes the kind of stereotypical behavior you describe. This is possibly due to cultural differences in what is expected of women, and partly due to the fact that it represents a kind of sexist pejorative commonly frowned on.

Which isn't to sat that this stereotype or the motivations for the behavior are unknown. Far from it. Both women and men who expect to get married, but who have reached a certain age without doing so, may adopt any number of compensatory behaviors to make up for their disappointment. What is different is the relatively young age at which a woman can be called a "dried fish" in Japan, and the way the woman's behaviors contrast with what is expected from Japanese women.

But before I dive into a discussion of that, let's go over some terms that have been traditionally used for unmarried women past a "certain age":

spinster, maiden aunt, old maid, bachelor woman, independent woman, "her own woman", "confirmed bachelorette", career woman,

and various others. Note the exact value of this "certain age" varies considerably. One person or group might consider a woman of, say, 29 to be well past marrying age, while another would consider her to be in her prime.

In any case, none of these terms presumes the kind of despondent behavior you describe in your question. Someone you might call a "maiden aunt", for example, may dote on her sibling's children and display a high degree of motivation to cook for them, buy them presents, and take care of her own appearance in order to look nice when she visits them. An "independent woman" may choose to focus entirely on her career, and spend a lot of effort and money on her appearance if she feels it necessary for her success (or simply enjoys doing so).

Moreover it can be awkward to use any of these terms based on what can be considered a "traditional women's role", in modern society that tries not to impose these kind of restrictions. For example consider the highly lauded Megan Rapinoe, the 34-year old, openly gay, currently unmarried, co-captain of the world champion U.S. Women's Soccer team. In almost any context, calling her something like a "spinster" would be taken as an offensive slur against her gender, her age, and her sexual orientation, as well as a deprecation of her choice to be a professional athlete.

I couldn't say what terms the Japanese might use to describe Rapinoe, and whether those terms would be offensive if translated, but my point is that it's difficult to move an idiom like "dried fish woman" outside of its roots in Japanese culture. The best you can do is to describe the woman's age and marital status separately from her behavior, and then use qualifiers like "it seems" or "from her perspective" to mitigate any possible offense. For example (incorporating Ben's answer):

She feels like she's an old maid who is never going to get married, and so nowadays can't be bothered to make an effort to maintain appearances.

Again you might wish for a simple answer to the question, but all of those (including most of the previous answers) would be inaccurate. Moreover the idiom itself is highly derogatory, and should be used very carefully in order to avoid causing unwanted offense.

(Edit) Let me address an objection to this answer:

To start off, there can be little argument that the direct translation of the idiom into English is highly derogatory. The only question is whether there is some mitigating factor when used in Japanese that makes it less offensive. In the comments, Mitsuko suggests:

the term is originally negative, but some woman call themselves in this way, with the message being, "it is my lifestyle and I am happy with it"

It's not uncommon to find people who are resigned to a particular lifestyle, and who choose to make the most of it. Nevertheless the kinds of behavior described as characteristic of "dried fish women" belie any sense of joy. I have to assume that "happy" means something more along the lines of "I can't complain" than "My life is just how I want it". The women aren't using 干物女 as a point of pride, but rather as a defensive rejection of the assumption that their lives are somehow incomplete -- even as they act in a way that makes it seem their lives aren't as fulfilling as they might wish.

Alternately, a woman might call herself a 干物女 in the same way she might call herself an "old maid", but this is ironic self-deprecation, not redefinition.

So I remain unconvinced that the term is anything but a negative slur against "older" Japanese women. It might come across as mild scorn in Japan, but over here there's really no way to soften the impact. You might think something like "independent woman" is a happy medium, but not when the subtext is "old maid".

Now, it would be different if Japanese women did things like proudly wear t-shirts with 干物女 printed on the front as defiance of stereotype and custom, in the same way women in the U.S. wear shirts saying "Nasty Woman" in defiance of Donald Trump. If that's the case, I'm willing to revise my answer.

To let oneself go means to

fail to maintain an attractive physical appearance.

For the aspects that are physical, and the general "giving up" attitude, "she let herself go" fits quite nicely.

I looked up this term in Japanese Wikipedia, which says:

干物女とは恋愛を放棄している、様々な事を面倒臭がり適当に済ませてしまう女性のこと。

If I'm getting the sense right, it means, roughly, "a woman who has abandoned love, and finds the various details of her life bothersome and handles them in a lazy or careless manner."

The article goes on to say that the term 干物女 comes from a manga series by Hiura Satoru, which has been adapted for television and film.

Certainly the exemplar of such a person exists in many cultures, but names like "dried fish woman" nevertheless will not translate effectively into other languages: the overtones simply head in the wrong direction. For example, in English referring to a woman as "dried up" would likely mean someone who is barren or post-menopause, etc., but it would not mean she has "abandoned love," at least not deliberately.

Additionally, the person illuminated in the manga series would have a number of overtones accessible only to readers of the series, further complicating the process of finding a good translation.

From what I'm hearing, I would call such a person "walled off" and would judge her very likely to be clinically depressed. But I can't think of a single really good term that has one foot in the Japanese and the other solidly in English.

There is no direct equivalent phrase, in the sense that the exact list of qualities would not be associated with an English phrase. The connotation is also tricky - a connotative match would have to be both negative and reclaimed by some of these women. It is exceptionally unlikely that you'll find a denotative and connotative match to something so specific. Thus a translator would have to decide which sense to emphasize in a given situation.

For this answer, I focus on a match to the literal sense of the term, since the connotative match is so difficult. A more prosaic phrase that captures much of the literal meaning is independent woman: a woman who works and lives her life free of dependence on a relationship. If you are writing for translation today, the term would primarily be used for the more positive, reclaimed sense of the word dried fish woman - the ones who view such a woman as "rational self-sufficient loner women who live just for themselves." (Comment to question by Mitsuko, above.)

History

The term is present at least as far back as the 19th and early 20th centuries, where it referred to women who worked in factories, as teachers, or in other service jobs. This early letter in a periodical called The Texaco Star (1916) represents early stereotypes of such women that resemble what you list:

Economically the so-called independent woman is important and rates high. She earns money - that accounts for her rating. I wonder how many men enjoy working just for themselves? The independent woman does that. Sometimes she has parents or a husband to support, but for the most part she works for herself.

It turns out she's thirty years old or older.

I am speaking of the independent woman past thirty years of age, the ones who probably will be independent forever. One sees them by the thousands - well dressed, dependable -

They have a "dead look," attributed by the letter writer to lacking a husband or family to live for. So, at least in the phrase's early history, the idea that she has lost desire for men or family or life itself is present.

but the dead look in their eyes tells the discerning observer that the most of them would give away their wonderful independence in the twinkling of an eye for something real to live for. [...] I have met a great many of these women - stenographers, saleswomen, teachers, librarians - and it is the tragic truth that they are a restless and embittered class. A vast number of these decent, efficient women are real women; they have emotions and the right desire for a mate and a home. They have just been cheated of a woman's normal life, just as much as if they were medieval nuns or the victims of war.

The expression was also claimed as a label for the working woman. A periodical called The Independent Woman was published from 1920 to 1956, after which it changed its title to National Business Woman (source). The label was pragmatic - women who worked enjoyed economic independence. For some people this independence was negative because it separated women from traditional family structures. For other people this independence was liberating.

Usage Today

By the present day, an independent woman has become a more positive label in most contexts. Its negative qualities tend to survive in the prejudices of some commentators who believe that the so-called independence of such women is fake. For example, note the mingling of independence and negativity in these Urban Dictionary definitions and examples. Within the first entry, this sounds like the positive version of the independent woman:

A confident self motivated woman who takes responsibility for her actions and never blame the rest of the world for her mistakes or her downfalls. Her pride doesn't get in the way if she ever needs a helping hand.

But the definition author betrays prejudice in the example by writing about a woman who pretends to be independent but is actually lonely:

A women [sic], who is stubborn, rude, lonely and always saying that she is an independent woman, need to stop lying to herself and the people around her.

Meanwhile, this Wikipedia article sums up the expression's pop cultural history, and there are many more positive articles about the type like this one in the Huffington Post encouraging the independent woman.

Frequency

In terms of usage, this Google Ngram shows an uptick in usage after about 1980, whereas the near-synonym spinster (denoting an unmarried older woman) remains relatively stable. Meanwhile, the Corpus for Contemporary American English confirms 138 results for the phrase, with strong, fierce, and feminist all being common collocations. (Examples: "a strong independent woman," "a fiercely independent woman," "independent woman formed by the feminist struggles of the 1970s.")

So When Would You Use Independent Woman for Dried Fish Woman?

In one of the comments to your answer, you suggest that the label of the dried fish woman has been reclaimed by at least some women, who view independence from pursuing marriage and maintaining their appearance to be a positive step in their lives. For these women, independent woman would be an apt translation, representing a woman who does her own thing and earns her own way with less concern for appearances or depending on a marital partner.

For the more negative stereotype, independent woman would have once encompassed those negative qualities (a woman who has lost some of her spark because she is actually in need of a man whether she admits it or not), but today that usage only survives in rather misogynistic contexts like Urban Dictionary and in very traditionalist op-eds.