soundless

sound +‎ -less

soundless (comparative more soundless, superlative most soundless)

1. Without sound.
   • c. 1599, William Shakespeare, Julius Caesar, Act V, Scene 1,

     Cassius. […] for your words, they rob the Hybla bees,

     And leave them honeyless.

     Antony. Not stingless too.

     Brutus. O yes, and soundless too;

     For you have stol’n their buzzing, Antony,

     And very wisely threat before you sting.

   • 1663, Robert Boyle, Some Considerations Touching the Usefulness of Experimental Naturall Philosophy, Oxford: Richard Davis, Essay 2, p. 49,

     The Psalmist observes, That the Heavens declare the glory of God: And indeed, they celebrate his Praises, though with a soundless Voice, yet with so loud a one […] to our intellectual Ears, that he scruples not to affirm, that There is no Speech nor Language where their voice is not heard […]

   • 1797, Ann Radcliffe, The Italian, London: T. Cadell Junior & W. Davies, Volume 2, Chapter 7, p. 225,

     The whole building, with its dark windows and soundless avenues, had an air strikingly forlorn and solitary.

   • 1839, Edgar Allan Poe, “The Fall of the House of Usher” in Burton’s Gentleman’s Magazine, Volume 5, September 1839, p. 145,

     During the whole of a dull, dark, and soundless day in the autumn of the year, when the clouds hang oppressively low in the heavens, I had been passing alone, on horseback, through a singularly dreary tract of country […]

   • 1896, A. E. Housman, A Shropshire Lad, London: Grant Richards, 1898, XXXVIII, p. 55,

     The names of men blow soundless by,

     My fellows’ and my own.

2. Not capable of being sounded or fathomed.
   • 1609, William Shakespeare, Sonnet 80,

     Your shallowest help will hold me up afloat,

     Whilst he upon your soundless deep doth ride;

   • 1614, Christopher Brooke, The Ghost of Richard the Third, London: L. Lisle, “The Legend of Richard the Third,”

     Nor Wits, nor Chronicles could ere containe,

     The Hell-deepe Reaches, of my soundlesse Braine.

   • 1881, Walt Whitman, “Out from Behind This Mask (To Confront a Portrait)” in Leaves of Grass, London: David Bogue, p. 296,

     This heart’s geography’s map, this limitless small continent, this soundless sea;

• (without sound): noiseless, silent.
• (not capable of being sounded): bottomless, depthless, fathomless, unfathomable.

• soundlessly
• soundlessness

• sound