brilliant vs brainy

brilliant and brainy both are adjectives.

Word	Noun	Adjective	Verb	Adverb
brilliant	No	Yes	No	No
brainy	No	Yes	No	No

As adjectives, brilliant and brainy are synonyms defined as:

brilliant and brainy: having or marked by unusual and impressive intelligence

Other synonyms of brilliant include smart as a whip.

brilliant (adjective)	brainy (adjective)
full of light; shining intensely	having or marked by unusual and impressive intelligence
having strong or striking color
characterized by grandeur
having or marked by unusual and impressive intelligence
clear and sharp and ringing
of surpassing excellence