Help needed

[alexia]

Hello, can you help? I have to explain why in the expression 'I'm in a hurry' we use the article 'a', and we cannot say: 'I'm in hurry'. Thank you very much.

[Tdol]

Though we don't use the plural much, if at all, it's a singular countable noun.

[alexia]

Thank you very much, but my problem is related to the translation into my L1 language: Italian, and it doesn't correspond to the one in English with the article, so can I say that 'in a hurry' is an idiomatic expression, or a fixed expression? Please help!!

[Casiopea]

"hurry" functions as a noun and it means, great or eager haste. Nouns require an article:

What's the hurry?
I'm in a hurry.

Moreover, the word "in" is a preposition, and prepositions require nouns as their objects:

I'm in a rush.
I'm in a house.
I'm in trouble. (In this case, 'trouble' comes from an adjective, so when it functions as a noun, it doesn't require an article.)

The adjectival form of "hurry" is hurried:

He is a man. (noun)
He is a hurried man. (noun, adjective)