INVULNERABLE

invulnerable

(adjective) immune to attack; impregnable; “gunners raked the beach from invulnerable positions on the cliffs”

Source: WordNet® 3.1

Etymology

Adjective

invulnerable (not comparable)

Incapable of being injured; not vulnerable.

Unanswerable; irrefutable

Source: Wiktionary

In*vul"ner*a*ble, a. Etym: [L. invulnerabilis: cf. F. invulnérable. See In- not, and Vulnerable.]

1. Incapable of being wounded, or of receiving injury. Neither vainly hope To be invulnerable in those bright arms. Milton.

2. Unanswerable; irrefutable; that can not be refuted or convinced; as, an invulnerable argument.

Source: Webster’s Unabridged Dictionary 1913 Edition