What is the noun form of complment?

There is no Word in English spelled 'complment'. This makes it difficult to know if you are asking about the noun complement or the noun compliment; they are both nouns which have different meanings.

The noun complement is a singular, common, abstract noun; a Word for something that is added to something else; something that combines well with something else; a number or quantity of something required to make a group complete.

The noun compliment is a singular, common, abstract noun; a Word for an expression of respect, affection, or admiration; an admiring remark; praise.