sleeper

the word "sleeper" is a transparent compound from the germanic linguistic tradition. its first element, "sleep," descends from the old english verb 'slæpan', which has cognates across germanic languages, all tracing back to the proto-germanic root 'slēpaną', meaning to be slack or limp—a vivid description of the body's state during rest. the agentive suffix "-er," from old english '-ere', is a prolific noun-forming element indicating "one who does" something. therefore, the literal meaning is "one who sleeps." this core meaning was logically extended to objects associated with sleep, such as a sleeping car on a train. the modern figurative sense, describing something that becomes successful after initial obscurity, is a metaphorical extension from the late 19th century, likening the hidden potential to a person or thing lying dormant before awakening to prominence.

Structure: sleep (to rest in a state of natural unconsciousness) + er (agent suffix) "sleep" is from old english 'slæpan', a verb meaning to rest in a state of natural unconsciousness. the suffix "-er" is from old english '-ere', an agent suffix used to form nouns indicating a person or thing that performs an action.