calm, cool, and collected; level-headed
Describes a composed, unflappable attitude, especially under pressure. Often used to praise someone's steady demeanor.
He remains calm and collected in any situation.
A level-headed decision is required.
冷静 is a common word for 'calm' or 'cool-headed'. 冷静沈着 is a stronger, more emphatic yojijukugo emphasizing complete composure.
沈着 alone means 'composure' or 'self-possession', but is less common than 冷静沈着. The compound reinforces the idea of unshakable calm.
A yojijukugo combining 冷静 (calm, cool-headed) and 沈着 (composure, self-possession). The exact historical derivation is uncertain, but the compound is conventionally associated with a composed and unflappable demeanor.