Synonyms for Voiceless (same or very similar meaning)
WordNet sense 1 (produced without vibration of the vocal cords):
hard, unvoiced, surd
WordNet sense 2 (deprived of the rights of citizenship especially the right to vote):
disenfranchised, disfranchised, voteless
WordNet sense 3 (uttered without voice):
breathed
WordNet sense 4 (impossible to hear; imperceptible by the ear):
inaudible, unhearable
WordNet sense 5 (being without sound through injury or illness and thus incapable of all but whispered speech):
aphonic
WordNet sense 6 (without or deprived of the use of speech or words):
inarticulate, unarticulate
From the ODE community, based on WordNet
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