Squiggly means having a wavy, curvy, or wiggly shape instead of being straight. A squiggly line twists and turns unpredictably, like when you draw without lifting your pen while moving your hand in random directions.

You see squiggly shapes everywhere: in cursive handwriting that flows across the page, in the path of a snake moving through grass, or in the way a piece of cooked spaghetti lies on your plate. When you draw an equal sign in math, you make two straight parallel lines, but when mathematicians want to show that something is approximately equal, they use a squiggly equal sign that looks like a tiny wave (~).

Kids often make squiggly doodles in the margins of their notebooks. Artists might add squiggly details to their drawings to show water, smoke, or movement.

If someone's handwriting is hard to read because the letters curve and bend in unusual ways, you might call it squiggly. The word captures that sense of something being bendy and irregular in a loose, casual way, rather than following straight lines or predictable curves.