'Rocket scientist' definitions:

Definition of 'rocket scientist'

From: WordNet
noun
A clever thinker; "you do not have to be a rocket scientist to figure that out"
noun
An engineer who builds and tests rockets [syn: rocket engineer, rocket scientist]

Definition of 'Rocket scientist'

From: GCIDE
  • Rocket scientist \Rock"et sci"en*tist\, n. 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. [PJC]