necessity vs want

necessity and want both are nouns.

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

As nouns, want is a hyponym of necessity; that is, want is a word with a more specific, narrower meaning than necessity:

Other hyponyms of necessity include desideratum, must, need.

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

necessity (verb)	want (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