What is the meaning of the word "cool"?

Definitions:

(used of a number or sum) without exaggeration or qualification adjective
- a cool million bucks
great coolness and composure under strain noun
- keep your cool
marked by calm self-control especially in trying circumstances; originally AAVE adjective
- I like to think that I'm pretty cool in stressful times.
the quality of being at a refreshingly low temperature noun
- the cool of early morning
to loose heat verb
- The air cooled considerably after the thunderstorm
to lose intensity verb
- Our enthusiasm cooled considerably.