I said that explicitly so that you wouldn’t think it was some kind of gotcha, so I don’t know why that was your reply. Not all dictionaries agree with MW.

It’s called an attributive noun, by the way.

I feel like the fact that you aren’t subscribing to “the salt is table” usage, nor coming up with any nouns that are not adjectives, indicates you also don’t really think that attributive nouns are adjectives. So let’s disagree with Merriam-Webster together! Yay!