Voiceless

a.
  1. Having no voice, utterance, or vote; silent; mute; dumb.
  2. (Phon.) Not sounded with voice; as, a voiceless consonant; surd.
  3. Voiceless stop (Phon.),
    a consonant made with no audible sound except in the transition to or from another sound; a surd mute, as p, t, k.