Quote by DanielleX
In the context of a leather sofa, leather is a noun. A leather sofa is itself a thing, 'leather' doesn't qualify sofa it merely says what it is. I can't say leather can never be an adjective but leathery is the normal form.
I believe that in this case, you have a word that's commonly a noun which is being employed as an adjective. Words can change their initial nature in many instances:
"I always strive for the good."
Here you have an adjective that's being used as a noun.
"I swear, I once encountered a talking cat!"
Here you have a verb that's being used as an adjective.










