Are there nouns that undergo no change when used in the possessive (Saxon genitive)?

I’m looking for the existence of English nouns (common or proper) that undergo no change when used in their possessive (Saxon genitive) form, i.e. that do not take the usual ’s appendage the way radio’s, or Paul’s would. If there exist nouns that end with s or x, and for which the single possessive apostrophe ’ is widely accepted as being optional, then that would count too.

My understanding is that every possessive noun either takes ’s or just ’, but can’t confirm.

My question is specifically about the genitive form., i.e. Bob's car, desk's surface, crucifix'.

Since posting this question originally, I've learned a bit more about some of the taxonomy on the subject. I thought initially that the lack of apostrophe in phrases such as “boyscout club chocolate’s bitter taste” may have been a hint nouns didn't need an apostrophe in certain cases. But they're a different case.

Many have been quick to point out noun-noun compounds functioning as attributive nouns, such as in telephone pole, glee club or mountain rock peaks to express relative notions of "ownership"/"possession". Or that prepositions can also be introduced to express possession, e.g. "The book of Peter".

But, I do not mean to ask about attribute nouns, nor "x of y" constructions.

Do all nouns take the 's or ' when used on their own in the genitive?

Edit

Similar posts:

• Discussion on whether mens or womens takes an apostrophe. Did not initially find that question because it was specific to those two instances of words. In my original post I'd mentioned whether womens and childrens without apostrophe would be considered to be spelled correctly, without suspecting I'd be stepping into a whole slew of other posts.

• Using possessive nouns in the plural. I’ve found a similar, but different question here on possessive nouns in the plural. This kind of is what I'm looking for, but it's more about transforming nouns into attributive nouns, than nouns that don't need the apostrophe because of their nature.

• It’s been pointed out that in some countries, namely US and Australia, possessive apostrophes are deprecated in place names. That is sort of the answer I'm looking for, but only if the last token in the chain of nouns would normally take a 's. Are there more such cases in other fields?

I do feel at this point that the answer to my question is kind of spread on a million different questions.

I think you might be mistaking attributive nouns in noun–noun compounds for possessive nouns with apostrophes, but I’m not completely certain.

When you have a child entertainer, the word child is used attributively not possessively. A noun or noun phrase in English is only considered possessive when it is written with an actual apostrophe, as you would have with my child’s entertainer or a my children’s entertainer. Those are both possessives.

If you’re asking about spelling rather than pronunciation or grammar, then please see this answer.

The only time you do not write an apostrophe for a possessive in English is when you have a personal pronoun (like mine and theirs) or the corresponding possessive determiners (like my and their).

In all other situations, you must write an actual apostrophe. This is true whether your possessive is being applied to a single word like England’s defenders or to an entire noun phrase like the Queen of England’s hat.

In your example of “boyscout club chocolate’s bitter taste”, the compound noun boyscout club chocolate is being used possessively, which you can tell because the entire set gets an apostrophe-s added to it. A boy scout is using boy as an attributive noun, not as a possessive one. And a boyscout club is again using boyscout as attributive noun, not as a possessive one. Finally, in boyscout club chocolate the two or three nouns before chocolate are all being used attributively not possessively. The only possessive is the apostrophe-s on the whole compound noun. The others are attributive.

This possessive apostrophe that we use here is merely an accepted convention for how we represent possessives in writing. Many people become confused about how to write these, but few if any are ever confused about how to say them.

The speech-rule used to create and pronounce a possessive is the same phonological rule we use to make regular plurals out of regular singulars. We do this by adding one of several phonetically determined variants of an /S/ archiphoneme: either the [s] or [z] sound, or an unstressed [əz] sound adding a new syllable, or in a few cases even no sound at all. (Some people do have a different reduced vowel there than [ə], usually [ɨ], but this is not phonemic for most of them.)

But whereas creating plurals has many historic exceptions that do not use this phonetic rule, like when we say geese or mice or children, pronouncing possessives has zero exceptions. We always pronounce a possessive using one of those various phonetically determined variants of the /S/ archiphoneme.

Which one we happen to use is not indicated by the spelling; you have to know and follow certain phonological rules. That’s why witch’s and witches and witches’ are all written differently even though they are pronounced identically. The apostrophe has been adopted as a writing convention to tell readers which ᴡɪᴛᴄʜ word is meant to be a possessive.

If for whatever reason you choose to ignore the standard writing convention of using an apostrophe to mean a noun or noun phrase should be considered possessive, then you run the risk of being misunderstood or thought less of by those who think this somehow matters.

Of course in speech you have no such trouble, since the pronunciation rule is wholly regular. That and because speech has no punctuation for people to argue about. :)