Improper use of "cavalry"?

Basically, what it comes down to is that this other person is saying "cavalry" is an adjective. It's not. It's a noun. "A few horses short of a cavalry" is perfectly fine. I'd say "the cavalry" is more common than "a cavalry," but you need to say "a cavalry" for your idiom to make sense.

The other person is right about one thing. "Airborne" is an adjective, so "an airborne" would indeed make little sense. But his comparison of "airborne" and "cavalry" is totally off.

Well, technically... He's correct in the fact that it doesn't make sense.

It's like saying... You're a few cars short of a race.

A race is an event. Adding cars, or subtracting cars doesn't change the fact that a race is a race.

A cavalry doesn't become less of a cavalry if you remove some of the horses. It's either a cavalry or it's not.

So, he's correct.

NOOOO - you're wrong. Look up countable versus uncountable nouns.

When you put the article 'a' in front, you signify you are dealing with a countable noun. Those are things you can count. Happy meals fit - one Happy Meal, two Happy Meals, etc.

But cavalry is not countable - you don't go one cavalry, two cavalries. Instead, you use a countable noun + an of phrase - one troop of cavalry, two troops of cavalry.

the point is that it takes at least 2 horses and two soldiers to make a cavalry...if your "a few short" then the obvious inference is that you don't have what it take to "make it"

that's no different than "few chicken nuggets short of a Happy Meal" or "several rolls shy of a Bakers dozen", which are similar euphemisms.

your friends analogy is "close, but no cigar"

When what you intend to mean, is that a person is not very bright, the way you said it would be correct. The entire sentence is said in jest, and the more incorrect it is grammatically, the better it makes your point. Good Luck