coolheaded
cool·hea·ded
adjective
1.
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”
Origin
From cool + headed, thus "having a cool head."
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.