Soundless

Sound′less

,

Adj.

Not capable of being sounded or fathomed; unfathomable.

Shak.

,

Adj.

Having no sound; noiseless; silent.

–

Sound′less-ly

,

adv.

–

Sound′less-ness

,

Noun.

,

Adj.

That cannot be fathomed; having no sound.

soundless ‎(comparative more soundless, superlative most soundless)

without sound
- 1599, William Shakespeare, Julius Caesar, V. i. 37:
  O yes, and soundless too; / For you have stolen their buzzing, Antony, / And very wisely threat before you sting.
Not capable of being sounded or fathomed; unfathomable.
- 1609, William Shakespeare, Sonnet 80:
  Your shallowest help will hold me up afloat, / Whilst he upon your soundless deep doth ride,

without sound

Lithuanian: begarsis
Russian: беззву́чный (ru) ‎(bezzvúčnyj), бесшу́мный (ru) ‎(besšúmnyj) (noiseless)