From Longman Dictionary of Contemporary Englishairtightair‧tight /ˈeətaɪt $ ˈer-/ adjective 1 TAIRnot allowing air to get in or out airtight containers2 planned or done so carefully that there is no chance of any problems or mistakes SYN watertight an airtight alibi
Examples from the Corpus
airtight• Security was airtight.• If hydrogen sulfide or some other poisonous gas is detected, Donahue dons an airtight breathing device and a hard hat.• Store cookies in an airtight container.• Uncooked madeira cake mixture can be frozen in an airtight container.• Now there was the sound of a seeming kiss as an airtight hatch in the bottom of the saucer was opened.• Sealing food in an airtight jar starves the bacteria of oxygen and they are unable to reproduce.• This is the reason you will notice jar lids advertising airtight seals and warning against consumption when the seal is broken.• He wears a white helmet that is sealed to his airtight suit and he strides to the unmarked plane without delay.• The game warden and the biospherians were facing each other on either side of a thick airtight window. 