Adjectives versus Noun Adjuncts [duplicate]

What determines whether something is a "noun adjunct" or just a garden-variety adjective? Does it matter in any meaningful way?

Here is my hypothesis, but I can't find any authoritative source to back it up. I'm hoping someone here can weigh in more definitively.

  1. Classification of noun adjuncts is based subjectively on whether the word is in "common usage" as a noun. "Book" and "chicken" are commonly nouns and would be considered noun adjuncts in "book collector" and "chicken soup"; "yellow", not so much.
  2. Noun adjuncts may share some common qualities that differentiate them from other adjectives (like not being able to be inflected into superlative forms... one can't be a "book-est collector"). But they are still fundamentally adjectives and may even appear in the dictionary as such if the adjectival usage is common enough.

What I've found so far...

Wikipedia defines a "noun adjunct" as:

an optional noun that modifies another noun; it is a noun functioning as an adjective.

But English words are not decreed to be nouns or adjectives by some higher authority. So it seems strange that one can prescriptively conclude that something "is a noun" in the first place, let alone extrapolate that it "is a noun functioning as an adjective".

The wiki article cites "chicken soup" as an example of a noun adjunct, but at least one dictionary gives a definition for "chicken" as:

adj. (of food) containing, made from, or having the flavor of chicken

So it seems that there are some differing points of view on how to categorize these words.

This question was spawned from some discussion in this question, this question and this other question.


But they are still fundamentally adjectives

Here's where I disagree with the rest of your description, that I otherwise think is correct.

If such a word is "fundamentally" anything (I'll come back to that "if"), it's fundamentally a noun: We think of it as a noun in the abstract. We can't inflect it like like an adjective because it isn't one (though other adjectives may not be able ). They are being used as adjectives, but take them away from that use and their adjectival quality is lost again.

and may even appear in the dictionary as such if the adjectival usage is common enough.

But then it has developed an adjective sense. Or rather, it developed such a sense, and then was recorded as such in the dictionary. Or rather, some lexicographer decided that it had developed such a sense and then recorded it; I'm not convinced the entry you link to was justified; "chicken hot soup" would still be wrong if chicken were accepted as an adjective for the material, but it would be less wrong. I suppose it depends in part in whether we consider "the soup is chicken" to be a contraction of "the soup is chicken soup" or not.

But English words are not decreed to be nouns or adjectives by some higher authority.

So there are no nouns at all?

So it seems strange that one can prescriptively conclude that something "is a noun" in the first place, let alone extrapolate that it "is a noun functioning as an adjective".

Who said anything about prescriptively concluding something "is a noun"?

Now one can prescriptively do so (you can't stop me!) and indeed everyone does; everyone prescriptively decides what they themselves will or will not write. If you decide you are prepared to write "the wall is kitchen" or that you are not, you're being prescriptive.

But we don't need to consider that either. Descriptively you can either observe that people do not generally say "the wall is kitchen" of a kitchen wall, and so it is not an adjective, or you can argue that they might, and so it is an adjective.

I said I'd come back to the "if" of "if such a word is 'fundamentally' anything", and it's because I don't think fundamentally makes sense for things like parts of speech. Parts of speech, especially the traditional parts of speech, are useful classifications. Just how useful is something linguists might debate, as they might also debate just what those parts of speech actually are and e.g. whether determiners are a type of quantifier or separate, and so on.

There are senses in English that can act as a name of a thing or set of things and we call them nouns. They can also be used to modify other nouns they precede, and we call that use noun adjuncts. There are other senses that modify nouns that way and also predicatively and with adverbs further modifying them, and we call them adjectives.

And this is useful up to a point, but I don't think there's anything fundamental about any of it.

There remain qualities that nouns have, even if used as modifiers, that adjectives do not, and therefore the concept of noun and adjective remain usefully separate.