1) Air-tight 2) Exclusively Saxon word 3) Exclusively Anglo word 4) Fictional corporal 5) Having no weak points 6) Hermetic 7) Impenetrable 8) Invulnerable 9) Irrefutable 10) Like good alibis 11) Like perfect alibis 12) Like some alibis 13) Sealed completely 14) Solid, alibiwise 15) Word of purely Anglo origin Found on https://www.crosswordclues.com/clue/airtight
preventing the entrance or escape of air or gas. · having no weak points or openings of which an opponent may take advantage: an airtight contract. Found on https://www.infoplease.com/dictionary/airtight