Synonyms and related words :
airtight, ballproof, bombproof, bulletproof, burglarproof, corrosionproof, dampproof, fire-resisting, fireproof, flameproof, foolproof, hermetic, holeproof, impassable, impenetrable, impermeable, impervious, impervious to, leakproof, noiseproof, nonpuncturable, proof, proof against, resistant, rustproof, shatterproof, shellproof, soundproof, tight, unpassable, unperforable, unpierceable, watertight, weatherproof