Unshakably calm and collected:
The definition of composed is calm.
Marked by calm self-control:
The definition of detached is separate or not connected, or not emotionally involved.
Having an even number in a sequence.
Without warmth or enthusiasm; showing cool lack of concern; casually indifferent
The definition of unflappable is not easily flustered.
Not agitated emotionally; calm:
Not agitated or excited; tranquil
Find another word for cool-headed. In this page you can discover 12 synonyms, antonyms, idiomatic expressions, and related words for cool-headed, like: imperturbable, composed, collected, cool, detached, even, even-tempered, nonchalant, unflappable, unruffled and calm.