Yes, hot is a noun, it could also be an adjective or an adverb. Example uses: Noun: You always know what is hot and what is not.Adjective: I would like some hot coffee.Adverb: Toast is at it's best...
nope, an adjective it isn't a noun because a noun is a person place or thing, and an adjective is a describing word, there for the word hot is an adjective.