n. A moderate degree of cold; a temperature between cold and heat: as, the coolness of the summer's evening.n. A moderate or refreshing sensation of cold.n. Absence of mental confusion or excitement; clearness of judgment and calmness of action, particularly in an emergency: as, the safety of the party depended on his coolness.n. Absence of ardor or intensity; want of passion, zeal, cordiality, or affection; indifference.n. Quiet and unabashed impudence; nonchalance; effrontery; presumption.