Nouns vs. nouns used as adjectives

Given the following sentence:

You should always use prefixes with your table names

Is the word table properly labeled as a noun or an adjective, as it is functioning as an adjective but the base word is a noun?

Context:

I am prefixing the words in some phrases with abbreviations. Some of the words are giving me trouble in classification. (The message is supposed to be an implicit proof of why adding prefixes to table names in a database is terrible. But I'd like to get it right.)

Here's the full set of sentences for your amusement. However, please restrict your comments to the stated question, for the most part.

1. com-Don't ver-Listen prep-To adj-Those adj-Other nou-People.


2. pro-You aux-Should adv-Always ver-Use nou-Prefixes prep-With pro-Your adj-Table nou-Names.


3. 
   

   pro-I aux-Have adv-Even ver-Started ver-Using pro-Them prep-In adj-Normal nou-Writing.

   
   


4. 
   

   com-See adv-How adj-Effective pr-It ver-Is?

   
   


5. nou-People aux-Can ver-Understand pro-Your nou-Writing adv-Better!

This question is part of 3 related questions:

1. Adjectives vs. determinatives


2. This question


3. Verbs vs. gerunds vs. something else

It originally came from this closed question

Answer

You should always use prefixes with your table names.

The word table is here a noun, not an adjective. The adjective would be tabular.

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Moreover, you should not say that it is “functioning as an adjective”, either. It is functioning as a noun adjunct—that is, as a noun modifying another noun.

Although all adjectives modify nouns,

not all things that modify nouns are adjectives!

The act of modifying a noun does not make an adjective.

Adjectives have other tests you can use to show that they’re adjectives, tests that nouns do not pass. And vice versa. For example, if it is an adjective, then you can use it as the predicate in a copula without changing the sense. Compare easy theory with an adjective versus game theory with two nouns.

• The theory is easy.


• *The theory is game.

That proves that game is still a noun, because it cannot be a predicate adjective here.

Because of how they modify nouns, adjectives can also generally be inflected by degree into comparative and superlative degrees, whether synthetically by inflection or analytically by adding more words.

Compare what happens when we attempt to form the superlative degree of easy theory and game theory. One the one with the adjective works, not the one with the noun:

• Easiest theory > The theory is easiest.


• *Gamest theory > *The theory is gamest.

That doesn’t work because again, easy is an adjective but game is a noun and so cannot inflect by degree like adjectives and adverbs can. There’s so such thing as a *gamest anything.

The relationship between by an attributive noun and the noun it modifies is not the same as that of an adjective modifying a noun, and so it is wrong to say that an attribute noun “functions” as an adjective. It does no such thing.