noun
unmarked police car
A police car without visible markings, used for covert patrol or surveillance.
覆面パトカーがスピード違反の車を追跡した。
An unmarked police car pursued the speeding vehicle.
A standard marked police car, unlike 覆面パトカー which is unmarked.
Compound of 覆面 (ふくめん, 'mask' or 'disguise') and パトカー ('patrol car').