imperviable
impervious
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
soundproofed
soundproofing
Plexiglas
bullet-proof
closet-sized
cost-free
frictionless
knotty-pine
peep show
playable
romanized
semipermeable
settled
ultra-light
undetectable
unnoticeable
unobtainable
unopposed
unusable
wood-paneled