grammar vs agree

grammar is a noun but agree is not a noun.

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

grammar (noun)	agree (noun)
the branch of linguistics that deals with syntax and morphology (and sometimes also deals with semantics)

grammar (verb)	agree (verb)
	be in accord; be in agreement
	consent or assent to a condition, or agree to do something
	achieve harmony of opinion, feeling, or purpose
	be agreeable or suitable
	be compatible, similar or consistent; coincide in their characteristics
	go together
	show grammatical agreement