shortfall vs deficiency

shortfall and deficiency both are nouns.

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

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

shortfall: 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 shortfall include inadequacy, insufficiency.

shortfall (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
	the state of needing something that is absent or unavailable