1. in a way that cannot be attacked, defeated, or overcome; invincibly

Examples

• The castle was impregnably fortified against enemy attacks.
• Her argument was impregnably logical and could not be refuted.
• The mountain fortress stood impregnably on the cliff face.
• The team’s defense was impregnably organized throughout the game.
• His reputation remained impregnably intact despite the scandal.
• The vault was impregnably secured with multiple layers of protection.