unfit vs modify

unfit is an adjective but modify is not an adjective.

Word	Noun	Adjective	Verb	Adverb
unfit	No	Yes	Yes	No
modify	No	No	Yes	No

As verbs, modify is a hypernym of unfit; that is, modify is a word with a broader meaning than unfit:

Other hypernyms of unfit include alter, change.

unfit (adjective)	modify (adjective)
not in good physical or mental condition; out of condition
below the required standards for a purpose
physically unsound or diseased

unfit (verb)	modify (verb)
make unfit or unsuitable	make less severe or harsh or extreme
	add a modifier to a constituent
	cause to change; make different; cause a transformation