Is "act like a mensch" too localized for ELU readers (U.S. and/or British English)?

This question was motivated by an interesting comment that was made at https://academia.stackexchange.com/posts/comments/123681?noredirect=1

Part of Answer: I don't think that particular research team would be a healthy place for you. The guy behaved badly. You need an advisor you can trust to act like a mensch.

Interesting Comment: Your "be a mensch" comment might be a little localised for American English, I (as a British English / German speaker) wondered why you were telling them to "be a human" before realising it was probably a Yiddish import from the American Jewish community with the appropriate semantic shift.

(I was using it in the decent human being sense; I checked the Wikipedia List of English words of Yiddish origin, and mensch does appear, in case that's helpful.)

Is "act like a mensch" too localized for ELU readers? Please say which variety of English you speak: American, British, Indian etc.

-- Edited to add: I would also like to know if the context made it clear enough or if I should go back and edit the Answer over on Academia and avoid using the word in future.

(If the conclusion is yes, then I will write a separate question asking for alternatives. So, please, no alternatives here—thank you!)

Nearly fifty years old, born in the UK, living in N. Italy for too many years, but a frequent visitor to the UK and Ireland: can't say I have never seen ‘mensch’ online, or that my mind exploded when I read the OP's sentence. By the way, should it be written with a capital letter?

In its proper context, the meaning of ‘mensch’ was easy enough to guess. But I'm used to guessing meanings: living in Italy there are so many different dialects, you have no choice but to develop a sense of intuition. I think this is a common characteristic among speakers of more than one or two languages.

However, if knowing its precise meaning of was of real importance, it's easy enough to look it up online. I would not recommend using this term in speech in the UK, unless you were sure your audience was familiar with the expression (and this holds true for the US as well), but it might be a handy trick in a presentation which is lagging pace; a humorous side-note added by the OP: "for the gentiles in the audience, ‘mensch’ is Yiddish for a person of honour". Said with a smile and a wink, it would be memorable.

UPDATE

I have just read the cited question on SE Academia, a very interesting read, and I would like to assure the OP that it would be impossible for any reader to interpret the Yiddish ‘mensch’ in his answer as being offensive or an insult. The context makes the meaning crystal clear, so I would advise the OP to not edit his answer. Moreover, the term is listed in Dictionary.com, one of the most visited online dictionaries, which hopefully dispels any worries that it is not acknowledged or accepted as being (also) English.

2nd UPDATE (Less than one year later)

The following was written by the ex-host of Top Gear, an Englishman called Chris Evans, for an article in the Mail Online (22:43 GMT, 9 July 2016)

The Top Gear gang are the most driven (forgive the pun) and dedicated I have ever worked with. There is nothing those guys won’t do to make every second of on-air content shine to its maximum potential.

Plus, I got to share the screen with Joey from Friends! May I just take a few lines to assure you what a total mensch and extreme petrolhead Matt LeBlanc is.

Which kinda proves that even Englishmen know the term and are confident enough to know how to use it correctly.

Link to The Guardian (for those who can't stomach the Daily Mail)

For me (native German speaker who spent some years working in England), this is exclusively an American word of Yiddish origin. I don't think I have ever heard this word in the UK or read it in British media. I would first assume it to be an allusion to Louise Mensch, who has been over the British media a lot in recent years. Sometimes German words are used in pretentious or sarcastic British English, as in "Herr Hitler" or "he likes to eat Wurst". This is the next interpretation I would try in a British context.

Mensch, though it sounded vaguely familiar as an American word, is sufficiently rare that I had to look it up for its precise sense. (The German sense is much more generic: man, human.)

Of course I don't know if native British English speakers have similar reactions.

But aren't you overdoing this? Two questions just to optimise the formulation of your original question?

PS: "Mensch", the established spelling as an English word, is actually the German spelling. The standard Yiddish spelling is of course in Hebrew letters, but the most common Latin transcription (YIVO) is "mentsh".

In German the word just means human (as a noun). The word is also used in German whenever English uses man in a way that includes women. Similar to the situation in English, Mensch and menschlich (the corresponding German adjective) are used in some contexts to imply the positive aspects of humanity related to solidarity between Mitmenschen (fellow humans). On the other hand, menschliche Schwächen (human foibles) are only menschlich (human), so in some contexts the negative aspects may be implied. In general there are gute Menschen (good men) and schlechte Menschen (bad men)

It appears that Yiddish (maybe especially Western Yiddish, which was spoken primarily in Germany?) basically shares the neutral or ambivalent nature of the word, but (maybe especially Eastern Yiddish?) gives more prominence to certain positive aspects. This may be due simply to culture (e.g. proverbs can have such an effect), or maybe Yiddish has a Hebrew word that competes with mentsh for the neutral meaning and thus makes it easier for it to shift.

Mensch as a loanword in English has completed this semantic shift in a way typical for loanwords. Since English already has words for the basic, neutral or ambivalent meaning, it has no use for anything but the special meaning. (Narrowed meanings like this are typical for loanwords. E.g. in Italian, a palazzo is just a big house - possibly an office building or an apartment building. The word gave rise to the loanword palazzo, which is even more specific than palace.)

If I understood it correctly, a mensch in English is a more or less ideal human, not according to Christian ideology - i.e. a saint, selfless - but in a much more pragmatic sense that reminds me of the Greek ideal of a balanced mind. (But without the physical aspects, which were equally important to ancient Greeks.)

As a native speaker of British English, I've never heard that phrase in my life and have no idea what it might mean. It's not a phrase I'd expect British people to understand, unless it's been used in one of the many American TV series that have been popular in the UK.

From my own experience, this is an idiom one can only use reliably in a diverse and cosmopolitan American milieu. I employ it with no hesitation if there are Jews present, because I am certain they will understand it. But educated people with a lot of multicultural awareness probably will as well.

It is not something one would be likely to use in, say, a Southern rural or blue-collar Northern gathering. But there is always a chance that media exposure will have enlightened a few.

As a native British-English speaker, who has lived in New Zealand for over 10 years, I have never heard this word before in either country.

I would say this is exclusively American-English, and probably only from certain big cities, as well. Its use is somewhat akin to my saying "I'm going to see the whanau" and expecting anyone outside New Zealand to understand me.