grammatic vs grammatical

grammatic and grammatical both are adjectives.

Word	Noun	Adjective	Verb	Adverb
grammatic	No	Yes	No	No
grammatical	No	Yes	No	No

As adjectives, grammatic and grammatical are synonyms defined as:

grammatic (adjective)	grammatical (adjective)
of or pertaining to grammar	conforming to the rules of grammar or usage accepted by native speakers
	of or pertaining to grammar