futile vs vain

futile and vain both are adjectives.

Word	Noun	Adjective	Verb	Adverb
futile	No	Yes	No	No
vain	No	Yes	No	No

As adjectives, futile and vain are synonyms defined as:

Other synonyms of futile include bootless, fruitless, sleeveless.

futile (adjective)	vain (adjective)
unproductive of success	characteristic of false pride; having an exaggerated sense of self-importance
producing no result or effect	unproductive of success