1. 
[syn: brainy, brilliant, smart as a whip]
The Collaborative International Dictionary of English v.0.48:
Brainy \Brain"y\ (br[=a]n"[y^]), a.
   1. Having an active or vigorous mind. [Colloq.]
      [1913 Webster]
   2. highly intelligent.
      [PJC] Braise
WordNet (r) 3.0 (2006):
brainy
    adj 1: having or marked by unusual and impressive intelligence;
           "some men dislike brainy women"; "a brilliant mind"; "a
           brilliant solution to the problem" [syn: brainy,
           brilliant, smart as a whip]
Moby Thesaurus II by Grady Ward, 1.0:
24 Moby Thesaurus words for "brainy":
   adroit, alert, apt, bright, brilliant, clever, dexterous, gifted,
   keen, keen-witted, knowing, nimble, nimble-witted, no dumbbell,
   not born yesterday, quick, quick-thinking, quick-witted,
   scintillating, sharp, sharp-witted, smart, steel-trap, talented