—v.t., v.i. 1. to synchronize (recorded sound) with lip movements, as of an actor in a film.
2. to match lip movements with (recorded speech or singing): She did a clumsy job of lip-syncing her big song.
—n. 1. the technical process by which this is done.
2. the simultaneous recording of voice and picture, esp. the synchronization of lip movements with recorded sound. Also,lip'synch",lip'sync".