Synonyms of bulletproof

1 Syllable
strong
3 Syllables
unyielding, armored, steel-plated, powerful
4 Syllables
impregnable, inviolable, invincible, impassable, unbeatable, untouchable
5 Syllables
indomitable, impenetrable, invulnerable, irresistible, unassailable, insuperable, unattackable, unconquerable, undefeatable, unsurmountable