coolheaded

• cool-headed

From cool +‎ headed, thus "having a cool head."

coolheaded (comparative more coolheaded, superlative most coolheaded)

1. Having an even temper; calm and collected
   • 1921, Edison Marshall, “The Heart of Little Shikara”, in O. Henry Memorial Award Prize Stories of 1921‎^[1]:

     There had been none among them coolheaded enough to reason out which trail he had likely taken, and thus look for him by the ford.

   • 1996 August 30, Jeffrey Felshman, “How to Win Enemies and Influence People”, in Chicago Reader‎^[2]:

     The heated rhetoric masked a more coolheaded strategy.

   • 2007 March 25, Liesl Schillinger, “The Evolution of a City, in Words and Pictures”, in New York Times‎^[3]:

     Some essays are coolheaded, some shake with hysteria, some are memoirish, others didactic.

• hotheaded
• reckless