I. ˈ ̷ ̷| ̷ ̷ adjective
Etymology: sound (III) + proof
: impervious to sound
a soundproof room
a soundproof studio
II. transitive verb
Etymology: back-formation from soundproofing
: to make soundproof : insulate so as to obstruct the passage of sound
called for soundproofing all floors, ceilings, and partitions