soundproof soundness • soundproofing · · · Info · Definitions · Characters · · soundproof · · Text Latin · · Script 10 · · Length Definitions · · · (verb) insulate against noise. Example: "Proust had his apartment soundproofed." · · Verb Definition 1 (adj) impervious to, or not penetrable by, sound. Example: "A soundproof room." · · Adjective Definition 1 Characters · · d latin small letter d U+0064 f latin small letter f U+0066 n latin small letter n U+006E o latin small letter o U+006F p latin small letter p U+0070 r latin small letter r U+0072 s latin small letter s U+0073 u latin small letter u U+0075