Wriggly describes something that twists, squirms, and moves in a wiggling, snakelike way. A worm is wriggly as it moves through the dirt. A fish is wriggly when you try to hold it in your hands. Puppies get wriggly when they're excited, twisting their whole bodies with joy.

The word often describes things that won't stay still. A wriggly little brother might squirm in his seat during a long car ride. Wriggly handwriting has letters that curve and wobble instead of sitting neatly on the line. You might draw a wriggly line to show a river on a map, or notice how a caterpillar makes a wriggly path across a leaf.

Things that are wriggly are rarely doing it on purpose to annoy you (though sometimes it can feel that way). They're just full of energy or built to move that way. The word captures that constant, restless, back-and-forth motion that makes something hard to hold onto or predict.