deficiency vs insufficiency

deficiency and insufficiency both are nouns.

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

As nouns, deficiency and insufficiency are synonyms defined as:

Other synonyms of deficiency include inadequacy.

deficiency (noun)	insufficiency (noun)
lack of an adequate quantity or number	lack of an adequate quantity or number
the state of needing something that is absent or unavailable	(pathology) inability of a bodily part or organ to function normally
	a lack of competence