silent in WordNet English dictionary

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