urgency vs necessity

urgency and necessity both are nouns.

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

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

urgency (noun)	necessity (noun)
pressing importance requiring speedy action	anything indispensable
insistent solicitation and entreaty	the condition of being essential or indispensable
the state of being urgent; an earnest and insistent necessity
an urgent situation calling for prompt action