To dither means to hesitate nervously, unable to make up your mind or take action. When someone dithers, they waffle back and forth between choices, wasting time in anxious indecision. Picture a student standing in the lunch line, unable to decide between pizza or tacos, holding up everyone behind them while going, “um, well, maybe, I don't know...”

Dithering happens when you get stuck in the decision itself instead of just picking something and moving forward. A team working on a group project might dither over what color to make their poster, spending twenty minutes debating when either choice would work fine. A chess player who dithers too long might run out of time on the clock.

The word carries a sense of unproductive anxiety. It's different from carefully thinking through an important decision. Dithering is more like spinning your wheels: lots of mental energy spent, but no progress made.