air-tight

CIDE DICTIONARY

air-tight, a. 

•  So tight as to be impermeable to air or other gases; as, an air-tight cylinder; -- said of containers.  [1913 Webster]
•  of such close construction as to have little leakage of air in or out; -- said of structures  [WordNet 1.5]
•  so thoroughly convincing as to be insusceptible to doubt; having no apparent counterarguments; -- of arguments or assertions  [PJC]

air-tight, n. 

 A stove the draft of which can be almost entirely shut off.  [1913 Webster]