Synonyms and related words :
barely audible, decrescendo, dim, distant, echoless, faint, faint-voiced, feeble, gentle, half-heard, hush as death, hushed, inaudible, indistinct, low, mousy, murmured, noiseless, pianissimo, piano, quiescent, quiet, scarcely heard, silent, soft, soft-sounding, soft-voiced, soundless, still, still as death, stilly, subdued, unarticulated, unclear, unhearable, unpronounced, unsounded, unuttered, unvocalized, unvoiced, weak, weak-voiced, whispered, whist