want vs necessary

want and necessary both are nouns.

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

As nouns, necessary is a hypernym of want; that is, necessary is a word with a broader meaning than want:

Other hypernyms of want include essential, necessity, requirement, requisite.

want (noun)	necessary (noun)
a specific feeling of desire	anything indispensable
anything that is necessary but lacking
a state of extreme poverty
the state of needing something that is absent or unavailable

want (adjective)	necessary (adjective)
	absolutely essential
	unavoidably determined by prior circumstances

want (verb)	necessary (verb)
wish or demand the presence of
have need of
hunt or look for; want for a particular reason
feel or have a desire for; want strongly
be without, lack; be deficient in