soundproof

from WordNet (r) 3.0 (2006)

soundproof
    adj 1: impervious to, or not penetrable by, sound; "a soundproof
           room"
    v 1: insulate against noise; "Proust had his apartment
         soundproofed"

from Moby Thesaurus II by Grady Ward, 1.0

28 Moby Thesaurus words for "soundproof":
      airtight, ballproof, bombproof, bulletproof, burglarproof,
      corrosionproof, dampproof, fire-resisting, fireproof, flameproof,
      foolproof, hermetic, holeproof, impervious to, insulate, leakproof,
      noiseproof, proof, proof against, punctureproof, resistant,
      rustproof, shatterproof, shellproof, tight, waterproof, watertight,
      weatherproof