1) Aphonic 2) Breathed 3) Dumb 4) Inarticulate 5) Inaudible 6) Silent 7) Surd 8) Unarticulate 9) Unhearable 10) Unspoken 11) Unsung 12) Unvoiced 13) Whispered 1) Lacking right of choice 2) Surd 3) Unvoiced 4) Uttered without voice 
• (a.) Not sounded with voice; as, a voiceless consonant; surd. • (a.) Having no voice, utterance, or vote; silent; mute; dumb.
Voice'less adjective 1. Having no voice, utterance, or vote; silent; mute; dumb. « I live and die unheard, With a most voiceless thought, sheathing it as a sword.» Byron. 2. (Phon.) Not sounded with voice; as, a voiceless consonant; surd. ...
Spoken without the vocal folds vibrating; the folds can either be open (the normal state) or closed with the compression of air between them and the supra-glottal stop position producing sounds which are called ejectives.