interrogative vs grammar

interrogative and grammar both are nouns.

Word	Noun	Adjective	Verb	Adverb
interrogative	Yes	Yes	No	No
grammar	Yes	No	No	No

interrogative (noun)	grammar (noun)
a sentence of inquiry that asks for a reply	the branch of linguistics that deals with syntax and morphology (and sometimes also deals with semantics)
some linguists consider interrogative sentences to constitute a mood

interrogative (adjective)	grammar (adjective)
relating to the use of or having the nature of an interrogation
relating to verbs in the so-called interrogative mood