mighty vs mightily

mighty is an adjective but mightily is not an adjective.

Word	Noun	Adjective	Verb	Adverb
mighty	No	Yes	No	Yes
mightily	No	No	No	Yes

As adverbs, mighty and mightily are synonyms defined as:

mighty and mightily: (Southern regional intensive) very; to a great degree

Other synonyms of mighty include powerful, right.

mighty (adjective)	mightily (adjective)
having or showing great strength or force or intensity

mighty (adverb)	mightily (adverb)
(Southern regional intensive) very; to a great degree	(Southern regional intensive) very; to a great degree
	powerfully or vigorously