make unnecessary vs forestall

make unnecessary and forestall both are verbs.

Word	Noun	Adjective	Verb	Adverb
make unnecessary	No	No	Yes	No
forestall	No	No	Yes	No

As verbs, forestall is a hypernym of make unnecessary; that is, forestall is a word with a broader meaning than make unnecessary:

Other hypernyms of make unnecessary include forbid, foreclose, preclude, prevent.

make unnecessary (verb)	forestall (verb)
make unnecessary an expenditure or effort	act in advance of; deal with ahead of time
	keep from happening or arising; make impossible