wiggly
Moving with lots of small, twisty, back-and-forth motions.
Wiggly describes something that moves with small, quick, twisting motions back and forth or side to side. A worm crossing the sidewalk after rain moves in a wiggly way, and a loose tooth feels wiggly when you touch it with your tongue. When you draw a wiggly line, it curves and bends instead of going straight.
The word captures a specific kind of movement: not big dramatic motions, but small, frequent shifts. A puppy's wiggly excitement shows in how its whole body seems to wiggle when greeting you. Jello is wiggly when you tap the bowl. A wiggly chair leg needs tightening because it shifts slightly instead of staying firm.
You might also describe someone as wiggly when they can't sit still, squirming and shifting in their seat during a long assembly. Young children often get wiggly after sitting quietly for too long because their bodies naturally want to move. The word suggests movement that's constant but not especially forceful, like how a fish wiggles through water or how your fingers look wiggly when you shake your hands very fast.