Jiggly describes something that shakes, wobbles, or moves with quick, bouncy trembles when you touch it or when it moves. A bowl of gelatin is perfectly jiggly: tap it with your spoon and watch it shimmy and quiver. Your cheeks might feel jiggly when you shake your head really fast, or a water balloon might feel jiggly when you toss it back and forth.

The word captures a specific kind of motion, softer and bouncier than a shake but more active than something that's simply soft. Jelly, pudding, and flan are all jiggly desserts. A puppy's belly might be jiggly, or the springs in an old mattress might make it feel jiggly when you jump on it.

Writers often use jiggly to make descriptions more vivid and physical. Instead of saying something is “unstable” or “moving,” calling it jiggly helps readers almost feel the wobbling motion themselves.