merge vs modify

merge and modify both are verbs.

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

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

Other hypernyms of merge include alter, change.

merge (verb)	modify (verb)
become one	make less severe or harsh or extreme
mix together different elements	add a modifier to a constituent
join or combine	cause to change; make different; cause a transformation