Jimmy is a short crowbar used to pry things open, especially by forcing apart a door and its frame. A jimmy is typically made of metal, flat on one end, and designed to slip into narrow gaps. The word also works as a verb: to jimmy something means to force it open with such a tool.

You might read in a mystery novel that someone jimmied the window, meaning they wedged a tool into the gap and pried it open. In everyday life, you might need to jimmy open a stuck drawer with a butter knife or flathead screwdriver.

The word can describe using any makeshift tool to force something open, not just an actual jimmy. If your locker jams and you use a ruler to pop it open, you've basically jimmied it. The term carries a hint of improvisation and force, suggesting you're working around something that's stuck or wasn't meant to open easily.