To muffle means to make a sound quieter or less clear, usually by covering or wrapping the source of the sound. When you muffle your cough with your hand during a quiet moment in class, you're trying to soften the noise so it won't disturb everyone. A heavy snowfall muffles the usual street sounds, making the world feel hushed and peaceful. Thick curtains muffle traffic noise from outside, helping you sleep better.

The word often implies that the sound becomes both quieter and harder to understand or identify. If you hear muffled voices through a closed door, you can tell people are talking but can't make out their words. A muffled thump from upstairs might leave you wondering what fell. Scarves, blankets, walls, and distance can all muffle sounds.

You can also muffle things besides sounds. Sometimes people muffle their true feelings, hiding their excitement or disappointment behind a calm face. But the core meaning stays the same: something that could be loud and clear becomes softer and less distinct, as if wrapped in layers of cloth.