You might say a person is as cool as a cucumber if he never seems to worry about anything and stays calm in a stressful situation.

VOA: special.2011.02.13

The purpose of immediate treatment is to cool the victim as quickly as possible to stop the body temperature from increasing.

VOA: special.2010.07.27

As he handed the basket to his wife, a sudden rush of cool rain put out the fire.

VOA: special.2009.02.28

Clouds with extremely cool water are mixed with man-made ice crystals, such as silver iodide and metaldehyde crystals.

VOA: special.2011.01.11

(SINGING) Choirs sang in the cool Sunday morning as family members laid flowers at tombstones of the victims of the 1960 Sharpeville Massacre.

VOA: standard.2010.03.21