unhearable

from WordNet (r) 3.0 (2006)

unhearable
    adj 1: impossible to hear; imperceptible by the ear; "an
           inaudible conversation" [syn: {inaudible}, {unhearable}]
           [ant: {audible}, {hearable}]

from Moby Thesaurus II by Grady Ward, 1.0

21 Moby Thesaurus words for "unhearable":
      echoless, hush as death, hushed, inaudible, mousy, noiseless,
      quiescent, quiet, silent, soundless, still, still as death, stilly,
      subaudible, unarticulated, unpronounced, unsounded, unuttered,
      unvocalized, unvoiced, whist

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