infallible
adaptable
airtight
ballproof
bombproof
bulletproof
burglarproof
certain
convenient
corrosionproof
dampproof
dependable
ductile
feasible
fire-resisting
fireproof
flameproof
flexible
guaranteed
handy
hermetic
holeproof
impervious to
leakproof
malleable
manageable
maneuverable
noiseproof
pliable
pliant
practical
proof
proof against
punctureproof
reliable
resistant
rustproof
safe
shatterproof
shellproof
soundproof
sure
sure-fire
tight
tractable
trustworthy
unfailing
untroublesome
warranted
watertight
believable
catatonic
flabbergasted
frictionless
impervious
invulnerable
nonexistent
painless
unassailable
unbreakable
undefended
undetectable
uninhabitable
unnoticeable
unobtainable
unopposed
unrecognizable
unscathed
unsinkable
untraceable
unusable
valueless
water-tight