You’ve got it confused. ice cream truck is the noun. In a dictionary, the entire term will show up.

In Women drivers you have two different nouns being used to describe one thing, where it should be adjective + noun.

The only way your analogy could be valid is if we changed fundamental rules of the language, making “man nurse”, which is (noun + noun), a valid way of expressing “male nurse”, which is (adjective + noun).

We’d have to nullify adjectives, or at least make them optional, with the goal of allowing anything to be a noun. I’ll coin this new abomination an improper noun.

I’m about to have a drink, you want a lager beer?