Soundless

Origin

sound + -less

Full definition of soundless

Adjective

1. without sound
• 1599, William Shakespeare, , V. i. 37:O yes, and soundless too;
  For you have stolen their buzzing, Antony,
  And very wisely threat before you sting.
2. Not capable of being sounded or fathomed; unfathomable.
• 1609, William Shakespeare, :Your shallowest help will hold me up afloat,
  Whilst he upon your soundless deep doth ride,