residue vs residual

residue and residual both are nouns.

Word	Noun	Adjective	Verb	Adverb
residue	Yes	No	No	No
residual	Yes	Yes	No	No

As nouns, residue and residual are synonyms defined as:

residue and residual: something left after other parts have been taken away

Other synonyms of residue include balance, remainder, residuum, rest.

residue (noun)	residual (noun)
something left after other parts have been taken away	(often plural) a payment that is made to a performer or writer or director of a television show or commercial that is paid for every repeat showing
matter that remains after something has been removed	something left after other parts have been taken away

residue (adjective)	residual (adjective)
	relating to or indicating a remainder