deficient vs insufficient

deficient and insufficient both are adjectives.

Word	Noun	Adjective	Verb	Adverb
deficient	No	Yes	No	No
insufficient	No	Yes	No	No

As adjectives, deficient and insufficient are synonyms defined as:

deficient and insufficient: of a quantity not able to fulfill a need or requirement

deficient (adjective)	insufficient (adjective)
of a quantity not able to fulfill a need or requirement	of a quantity not able to fulfill a need or requirement
inadequate in amount or degree
falling short of some prescribed norm