Rocket scientist

n.

1.

a very intelligent person; - used mostly in the phrases: "you don't have to be a rocket scientist to . . ." and "it doesn't take a rocket scientist to . . .", meaning that the subject that follows is easy to understand.

Noun	1.	rocket scientist - a clever thinker; "you do not have to be a rocket scientist to figure that out"
	2.	rocket scientist - an engineer who builds and tests rockets Synonyms: rocket engineer

thinker