'coolheaded' definitions:

Definition of 'coolheaded'

From: WordNet
adjective
Marked by calm self-control (especially in trying circumstances); unemotional; "play it cool"; "keep cool"; "stayed coolheaded in the crisis"; "the most nerveless winner in the history of the tournament" [syn: cool, coolheaded, nerveless]

Definition of 'coolheaded'

From: GCIDE
  • cool-headed \cool"-head`ed\, coolheaded \cool"head*ed\, a. Having a temper not easily excited; free from passion; unshakably calm and collected. -- {Cool"-head`ed*ness}, n.
  • Syn: cool, imperturbable, unflappable. [1913 Webster + WordNet 1.5]