Clunk is a heavy, dull sound, like dropping a thick book flat on a table or closing a car door that isn't quite aligned right. It's heavier and less musical than a clink or tap, suggesting something solid hitting something else without bouncing or ringing. When you hear a clunk, you know something with real weight just made contact.

The word captures both the sound and the feeling: clumsy, weighty, ungraceful. If your bicycle chain falls off and hits the pavement, that's a clunk. If you set down your overloaded backpack too hard, it might land with a satisfying clunk.

People also use clunk as a verb. When something clunks into place, it settles there firmly but without elegance. A machine that's working poorly might clunk and clatter instead of running smoothly. You might say an old car clunked down the street, describing not just the sound but the vehicle's rough, struggling movement.

The word can suggest something isn't working quite right or isn't as refined as it could be, but there's something honest and solid about a good clunk, too.