Marked by absence of sound:
— Soundless footsteps on the grass.

synonyms: silent, still.

Roget 208: deep, deep seated; profound, sunk, buried; submerged etc. 310; subaqueous, submarine, subterranean, subterraneous, subterrene^†; underground.    bottomless, soundless, fathomless; unfathomed, unfathomable; abysmal; deep as a well; bathycolpian^†; benthal^†, benthopelagic^†; downreaching^†, yawning.    knee deep, ankle deep.    ... show more

Roget 403: silent; still, stilly; noiseless, soundless; hushed etc. v.; mute etc. 581.    soft, solemn, awful, deathlike, silent as the grave; inaudible etc. (faint) 405.    ... show more