want vs necessity

want and necessity both are nouns.

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

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

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

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

want (verb)	necessity (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