necessary vs requisite

necessary and requisite both are nouns.

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

As nouns, necessary and requisite are synonyms defined as:

Other synonyms of necessary include essential, necessity, requirement.

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

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