If I describe a motor car as a 'four door car' I am making 'door' an adjective. It forms a compound adjective with the word 'four' and it adjectivally describes an attribute of the car, and is therefore singular as we do not inflect or pluralise adjectives in English.
Some people would hyphenate the compound adjective 'four-door'.
But I have overheard the expression 'four doored car' where the noun 'door' is (I assume) being made into a verb as we would make 'floor' into a verb ('the room was floored with linoleum' becomes 'a linoleum floored room').
Is this correct English ?
(I am referring to British English for context.)
Best Answer
No. Although it has an adjectival function.
You are using "door" as an attributive noun that, itself, is modified by "four".
four-door = noun phrase acting attributively.
The hyphen is not necessary, but if you use it, use it consistently:
Yes, "four-doored" is an adjective but it is rare and rather formal and I have not heard it other than as a predicative adjective - "The car is four-doored." You would usually say "The car is a four-door."