Keep (one's) cool American informal slang verb phrase
If you say that someone keeps their cool, you mean that they try not to lose composure, temper, or nerve
Everyone praised the kidnapped girl for keeping her cool and escaping miraculously from the human trafficker.
I can't believe that he kept his cool and dealt with those problems.
To not wonder, worry or be surprised about what is not predicted will happen in life because anything could happen
Used to advise somebody to calm down
Used to describe someone kind, calm and pleasant
To stay calm in a difficult situation and react to unexpected things quickly
The verb "keep" must be conjugated according to its tense.
This slang dates back to the mid-nineteenth century.
It was often said by a photographer when he would like small children to look at the camera and smile before he took a photo.
When the photographer said “watch the birdie”, all of us looked at the camera and smiled.