Entry 2 senses · 2 variants Webster, 1913 Soundless · Sound·less · IPA /ˈsaʊn(d)ləs/ a. a. 01 a. Not capable of being sounded or fathomed; unfathomable. 1. Not capable of being sounded or fathomed; unfathomable. 02 a. Having no sound; noiseless; silent. 1. Having no sound; noiseless; silent.