optimise vs modify

optimise and modify both are verbs.

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

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

optimise: modify to achieve maximum efficiency in storage capacity or time or cost
modify: make less severe or harsh or extreme

optimise (verb)	modify (verb)
act as an optimist and take a sunny view of the world	make less severe or harsh or extreme
make optimal; get the most out of; use best	add a modifier to a constituent
modify to achieve maximum efficiency in storage capacity or time or cost	cause to change; make different; cause a transformation