silent, soundless, still -- (marked by absence of sound; "a silent house"; "soundless footsteps on the grass"; "the night was still")
mum, silent -- (failing to speak or communicate etc when expected to; "the witness remained silent")
silent, tacit, understood -- (implied by or inferred from actions or statements; "gave silent consent"; "a tacit agreement"; "the understood provisos of a custody agreement")
silent, unsounded -- (not made to sound; "the silent `h' at the beginning of `honor'"; "in French certain letters are often unsounded")
silent -- (having a frequency below or above the range of human audibility; "a silent dog whistle")
dumb, mute, silent -- (unable to speak because of hereditary deafness)
(Sound)
