1. A sharp abrupt noise as if two objects hit together; may be repeated
   "The clack of high heels on the marble floor echoed in the hallway";
   - clap
    
2. A simple valve with a hinge on one side; allows fluid to flow in only one direction
   "The clack valve prevented the water from flowing back into the pump";
   - clack valve, clapper valve

1. Make a rattling sound
   "clacking dishes";
   - clatter, brattle [archaic]
    
2. Make a clucking sounds, characteristic of hens
   "The mother hen clacked to call her chicks";
   - cluck, click
    
3. [informal] Speak (about unimportant matters) rapidly and incessantly
   "The old man clacked on about the weather";
   - chatter, piffle [informal], palaver [informal], prate, tittle-tattle, twaddle [informal], maunder, prattle, blab [informal], gibber, tattle, blabber [informal], gabble, vapour [Brit, Cdn], vapor [US], rabbit [Brit, informal], jibber-jabber, witter [Brit, informal], twattle [UK, dialect], yatter [Brit, informal], yabber [informal]

Sounds like: claque

Derived forms: clacked, clacking, clacks

Type of: emit, let loose, let out, make noise, mouth, noise, resound, speak, talk, utter, valve, verbalise [Brit], verbalize

Encyclopedia: Clack, Peter