Nothing needs to be said to do it

HUM

Think of the quiet sound you might make when deep in thought or hesitating—it’s often done without words.

This clue plays on the idea of making a sound without using words. "Nothing needs to be said" hints at a noise you produce silently or without speaking—like humming, which is just a steady, wordless tune. The answer "HUM" fits because it’s both the sound itself and the action of making it.