silent

marked by absence of sound; "a silent house"; "soundless footsteps on the grass"; "the night was still"

failing to speak or communicate etc when expected to; "the witness remained silent"

implied by or inferred from actions or statements; "gave silent consent"; "a tacit agreement"; "the understood provisos of a custody agreement"

not made to sound; "the silent `h' at the beginning of `honor'"; "in French certain letters are often unsounded"

having a frequency below or above the range of human audibility; "a silent dog whistle"

unable to speak because of hereditary deafness