A sleeper (US English) or Q-car (British English) is a car that has high performance and an unassuming exterior.[1][2] Sleeper cars are termed such because their exterior looks little or no different from a standard or economy-class car. In some cases the car appears worse due to seeming neglect on the owner's part, typically referred to as "all go and no show". While appearing to be a standard or neglected car, internally they are modified to perform at higher performance levels. The American nomenclature comes from the term sleeper agent, while the British term derives from the Q-ships used by the Royal Navy.
