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lose your cool

vb. 1 (alternative form of lose one's cool English) 2 (en-third-person singularlose your cool)

Usage examples of "lose your cool".

You have the experience not to, um, lose your cool and force me to kill.

But if it challenges you to argue semantics with it, and you don't lose your cool .

So you could watch the old man drive away and maybe lose your cool.