An action which is intended to be perceived as a bluff, but which is not.

(idiomatic) Of a single resource, reserved for two different users at the same time.

A Weymouth bridle, which uses both a bradoon, held by a sliphead, and a curb bit, and is used with two reins.

A challenge that is harder or naughtier than a regular dare

To challenge with a double dare.

(sports) A game played between two teams, each consisting of a female and a male.

(law) The act of trying someone twice for the same offense, especially after an acquittal in the first trial.

(military) A fast marching pace of 180 steps per minute, 36 inches in length for the Marine Corps and Navy, 30 inches in length for the Army. It is not really double the speed of quick time as quick time is 112-120 steps per minute.

(physics) A characteristic of the transition of a system or process from regular motion to chaos, in which the period of one of its parameters is seen to double.

(rhetoric, usually derogatory) A phrase including two negative words (no, not, never, etc.) especially when used as intensifiers in informal English.