modify vs optimise

modify and optimise both are verbs.

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

As verbs, optimise is a hyponym of modify; that is, optimise is a word with a more specific, narrower meaning than modify:

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

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