Longman Dictionary of Contemporary English - cool

~1 adj 1 »TEMPERATURE« low in temperature, but not cold, often in a way that feels pleasant  (There was a cool breeze blowing off the sea. | sipping a cool drink)  (- see cold1) 2 »CALM« calm and not nervous, upset, embarrassed etc  (Now just stay cool. Everything's OK. | (as) cool as a cucumber (=very calm))  (Robert walked into the exam looking cool as a cucumber. | cool customer (=someone who behaves calmly in a difficult situation) | cool head (=ability to remain calm in a difficult situation))  (The job is quite demanding, so we need someone with a cool head. | cool, calm, and collected (=calm))  (Although she was nervous before the interview she managed to appear cool, calm and collected.) 3 »NOT FRIENDLY« behaving in a way that is not as friendly as you expect  (Her gaze was decidedly cool.) + towards  (The boss didn't actually say anything critical, but he was very cool towards me.) 4 »FASHIONABLE« informal very attractive, fashionable, relaxed etc, in a way that people admire  (You look really cool in those sunglasses.) 5 it's cool spoken used to say that something is not a problem  (Don't worry about the work - it's cool!) 6 »COLOUR« a cool colour is one, such as blue or green, that makes you think of cool things 7 a cool million/hundred thousand etc informal a surprisingly large amount of money that someone seems to earn very easily  (He earns a cool half million every year.) - coolness n - coolly adv - coolish adj ~2 v 1 also cool down to become cool or cooler, or make something do this  (You'll need to let your tea cool before you drink it. | They opened the windows to cool the room down.) 2 if a feeling, emotion, or relationship cools, it becomes less strong  (Our initial enthusiasm cooled when we saw how much work was involved.) 3 cool it spoken a) used to tell someone to stop being angry, violent etc  (That's enough arguing, you two - cool it!) b) to stop putting as much effort into something, or pressure on someone as you have been  (The more you chase after him, the less likely he is to go out with you. You'd better cool it a bit.) 4 cool your heels to be forced to wait  (The receptionist kept me cooling my heels for at least an hour.) cool down phr v 1 to become cool or cooler, or make something do this  (Let the engine cool down, and then try starting it. | cool sth down)  (Blow on your cocoa to cool it down.) 2 to become calm after being angry  (His father took a long time to cool down after their last argument.) cool off phr v 1 to return to a normal temperature after being hot  (We'd been in the sun all day, so went for a swim to cool off.) 2 to become calm after being angry  (Maybe you should go away and cool off before we talk any more.) ~3 n 1 the cool a temperature that is pleasantly cold + of  (They went for a stroll in the cool of the evening.) 2 keep your cool to remain calm in a frightening or difficult situation 3 lose your cool to stop being calm in an annoying or frightening situation  (I couldn't help it, I just lost my cool and started shouting at him.) ~4 adv play it cool to behave in a calm way because you do not want someone to know that you are really nervous, angry etc  (Don't worry, just listen to what they say and play it cool.)