This verb literally means to put something over the mouth—to bridle, muzzle, or silence. In Titus 1:11, Paul says false teachers must be silenced, their mouths stopped. The classical usage included bridling horses and curbing enemies, but also the technical sense of a flute player putting on the mouthpiece. The metaphorical sense of silencing a speaker was well-established. The multilingual evidence strongly emphasizes the silencing function: Spanish 'tapar-la-boca' (shut the mouth), French and German similarly direct. This is forceful language about stopping destructive speech.