weaken vs modify

weaken and modify both are verbs.

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

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

Other hypernyms of weaken include alter, change.

weaken (verb)	modify (verb)
become weaker	make less severe or harsh or extreme
lessen the strength of	add a modifier to a constituent
reduce the level or intensity or size or scope of	cause to change; make different; cause a transformation
lessen in force or effect
destroy property or hinder normal operations