deficiency vs need

deficiency and need both are nouns.

Word	Noun	Adjective	Verb	Adverb
deficiency	Yes	No	No	No
need	Yes	No	Yes	No

As nouns, need is a hypernym of deficiency; that is, need is a word with a broader meaning than deficiency:

Other hypernyms of deficiency include demand.

deficiency (noun)	need (noun)
lack of an adequate quantity or number	the psychological feature that arouses an organism to action toward a desired goal; the reason for the action; that which gives purpose and direction to behavior
the state of needing something that is absent or unavailable	anything that is necessary but lacking
	a condition requiring relief
	a state of extreme poverty or destitution

deficiency (verb)	need (verb)
	have need of
	have or feel a need for
	require as useful, just, or proper