im·preg·na·ble 
/ɪmˈprɛgnəbəl/ adjective
/ɪmˈprɛgnəbəl/ adjective 1 : not able to be captured by attack : very strong
▪ an impregnable fortress ▪ impregnable defenses 2 : not likely to be weakened or changed
▪ an impregnable reputation ▪ Her arguments seemed impregnable.
▪ an impregnable fortress ▪ impregnable defenses
▪ an impregnable reputation ▪ Her arguments seemed impregnable.
