A thud is a dull, heavy sound that happens when something solid hits a surface without bouncing or ringing. When you drop a thick book flat on a table, it makes a thud. When a basketball player misses a shot and the ball hits the rim instead of swishing through, you hear a disappointing thud.

The word captures both the sound and the feeling of heaviness. Compare it to lighter sounds: a pebble makes a tick or tap, but a dictionary falling off a shelf makes a solid thud. The word itself sounds like what it describes, with that heavy “uh” sound in the middle.

Thud works as both a noun (the sound itself) and a verb. Your heart might thud in your chest before giving a speech. Heavy footsteps thud down a hallway. When someone's brilliant idea fails completely, you might say it “landed with a thud,” meaning it fell flat and didn't create the excitement or success they hoped for.

Writers love using thud because it helps readers hear the scene. Instead of writing “the ball hit the ground,” they might write “the ball thudded on the ground,” making you feel the weight and disappointment of that missed catch.