'airtight' definitions:

Definition of 'airtight'

(from WordNet)
adjective
Having no weak points; "an airtight defense"; "an airtight argument" [syn: airtight, air-tight]
adjective
Not allowing air or gas to pass in or out [syn: airtight, air-tight, gas-tight]

Synonyms of 'airtight'

From: Moby Thesaurus