necessitate vs exact

necessitate is not an adjective while exact is an adjective.

Word	Noun	Adjective	Verb	Adverb
necessitate	No	No	Yes	No
exact	No	Yes	Yes	No

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

Other hyponyms of necessitate include claim, take, govern, draw, cost, cry for, cry out for, compel.

necessitate (adjective)	exact (adjective)
	marked by strict and particular and complete accordance with fact
	(of ideas, images, representations, expressions) characterized by perfect conformity to fact or truth; strictly correct
	lacking compromising or mitigating elements

necessitate (verb)	exact (verb)
require as useful, just, or proper	claim as due or just
cause to be a concomitant	take as an undesirable consequence of some event or state of affairs