hermetical
tight
abstruse
airtight
arcane
ballproof
bombproof
bulletproof
burglarproof
cabalistic
censored
chemic
classified
cloistered
close
closed
compact
concealed
corrosionproof
cryptic
dampproof
dark
deep
dustproof
dusttight
enigmatic
esoteric
fast
fire-resisting
fireproof
firm
flameproof
foolproof
gasproof
gastight
heavy
hermetically sealed
hidden
holeproof
hush-hush
impervious
impervious to
latent
leakproof
lightproof
lighttight
mysterious
noiseproof
occult
oilproof
oiltight
hermetically
Martian
O-ring
air-tight
axial-flow
closed-off
cuendillar
double-entry
existentialist
four-color
long-closed
peekaboo
safety-deposit
supersensuous
synoptic
talismanic
teeny-tiny
thermostatic
trifold
vacuum-sealed