Synonyms: gas-tight, air-tight, airtight
Definition: not allowing air or gas to pass in or out
Similar words: tight
Definition: of such close construction as to be impermeable
Usage: a tight roof; warm in our tight little house
Definition: having no weak points
Usage: an airtight defense; an airtight argument
Similar words: invulnerable
Definition: immune to attack; impregnable
Usage: gunners raked the beach from invulnerable positions on the cliffs