-proof-proof /pruːf/ suffix 
1[in adjectives] used to describe something which a particular thing cannot harm or pass through, or which protects people against that thing: 
a bulletproof car a waterproof jacket an ovenproof dish (=that cannot be harmed by heat)2[in adjectives] used to describe something which cannot easily be affected or damaged by someone or something: a childproof container vandal-proof3[in verbs] to treat or make something so that a particular thing cannot harm it or pass through it, or so that it gives protection against it: soundproof a room (=so that sound cannot get into or out of it)
1[in adjectives] used to describe something which a particular thing cannot harm or pass through, or which protects people against that thing: a bulletproof car a waterproof jacket an ovenproof dish (=that cannot be harmed by heat)2[in adjectives] used to describe something which cannot easily be affected or damaged by someone or something: a childproof container vandal-proof3[in verbs] to treat or make something so that a particular thing cannot harm it or pass through it, or so that it gives protection against it: soundproof a room (=so that sound cannot get into or out of it)