Entry 1 sense Webster, 1913 Inexpugnable · In·ex·pug·na·ble · IPA /ˌɪnɛkˈspʌɡnəbəl/ 01 a. Incapable of being subdued by force; impregnable; unconquerable. 1. Incapable of being subdued by force; impregnable; unconquerable. “A fortress, inexpugnable by the arts of war.” — Milman.