A device, usually mechanical, that is utterly unreliable and spends most of the timebroken or just barely in a working state, and comes this way from the manufacturing line. (Strangely common word in the model train world).
Dude 1: Hey whaddyou think about the P/T Cruiser?
Dude 2: Itβs a frickinβ lemon, man. Everybody knows that.