keep (one's) head
To be and remain in a calm, stable, sensible, and pragmatic state or condition despite stress. My father has always been a rock of level-headed judgment and advice. Even during our family's lowest points, he's always kept his head.
keep your head
COMMON If you keep your head, you remain calm in a difficult situation. Keep your head. A calm presence is an invaluable asset. The most important thing is to keep your head and focus on what you are doing. Compare with lose your head.
keep (or lose) your head
remain (or fail to remain) calm. 1990 Time He claims that Quayle rises to the challenge, takes chances but keeps his head.
keep your ˈhead
think clearly and remain calm: If there is a robbery, you should try to keep your head and do as you are told.