deficit vs deficiency

deficit and deficiency both are nouns.

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

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

deficit: the property of being an amount by which something is less than expected or required
deficiency: lack of an adequate quantity or number

Other hypernyms of deficit include inadequacy, insufficiency.

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

Other hypernyms of deficit include lack, want.

deficit (noun)	deficiency (noun)
the property of being an amount by which something is less than expected or required	lack of an adequate quantity or number
an excess of liabilities over assets (usually over a certain period)	the state of needing something that is absent or unavailable
(sports) the score by which a team or individual is losing
a deficiency or failure in neurological or mental functioning