requisite vs necessary

requisite and necessary both are nouns.

Word	Noun	Adjective	Verb	Adverb
requisite	Yes	Yes	No	No
necessary	Yes	Yes	No	No

As nouns, requisite and necessary are synonyms defined as:

Other synonyms of requisite include essential, necessity, requirement.

requisite (noun)	necessary (noun)
anything indispensable	anything indispensable

requisite (adjective)	necessary (adjective)
necessary for relief or supply	absolutely essential
	unavoidably determined by prior circumstances