A jalopy is an old, decrepit, unreliable and often nonfunctional car which has limited mechanical abilities and is often rusty or dented or in an unmaintained shape. A jalopy is not a well kept antique car, but a car which is mostly rundown or beaten up. As a slang term in American English, "Jalopy" was noted in 1924 but is now slightly passé. The term was used extensively in the book On the Road by Jack Kerouac, first published in 1957, although written from 1947.
The origin of the word is unknown. It is possible that the non Spanish-speaking New Orleans-based longshoremen, referring to scrapped autos destined for Jalapa, Mexico scrapyards, pronounced the destination on the palettes "jalopies" rather than multiples or possessive of Jalapa.
During the 1930s, this word was used frequently when the market for used cars first started to grow. Cheap dealers could obtain the cars for very little, make aesthetic adjustments, and sell the car for much more. Early hot rodders also purchased jalopies as the basis for racers, and early stock car racing would be called "jalopy racing".