Inexpugnably refers to something that is impossible to overcome or conquer. Synonyms for this word include impregnably, invincibly, indestructibly, unconquerably, and unassailably. These words all convey a sense of strength, resilience, and unbreakable defense. In terms of physical objects, they may refer to impregnable fortifications, castles, and walls that are impossible to breach. When used to describe people, they suggest individuals who are unshakeable in their beliefs, convictions, or resolve. The use of these synonyms is particularly common in military contexts, where commanders seek to fortify their positions or troops in the face of enemy attacks.