1. (superl.) Moderately cold; between warm and cold; lacking in warmth; producing or promoting coolness.

2. (superl.) Not ardent, warm, fond, or passionate; not hasty; deliberate; exercising self-control; self-possessed; dispassionate; indifferent; as, a cool lover; a cool debater.

3. (superl.) Not retaining heat; light; as, a cool dress.

4. (superl.) Manifesting coldness or dislike; chilling; apathetic; as, a cool manner.

5. (superl.) Quietly impudent; negligent of propriety in matters of minor importance, either ignorantly or willfully; presuming and selfish; audacious; as, cool behavior.

6. (superl.) Applied facetiously, in a vague sense, to a sum of money, commonly as if to give emphasis to the largeness of the amount.

7. (n.) A moderate state of cold; coolness; -- said of the temperature of the air between hot and cold; as, the cool of the day; the cool of the morning or evening.

8. (v. t.) To make cool or cold; to reduce the temperature of; as, ice cools water.

9. (v. t.) To moderate the heat or excitement of; to allay, as passion of any kind; to calm; to moderate.

10. (v. i.) To become less hot; to lose heat.

11. (v. i.) To lose the heat of excitement or passion; to become more moderate.