strengthen vs modify

strengthen and modify both are verbs.

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

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

Other hypernyms of strengthen include alter, change.

strengthen (verb)	modify (verb)
give a healthy elasticity to	make less severe or harsh or extreme
gain strength	add a modifier to a constituent
make strong or stronger	cause to change; make different; cause a transformation