| Impregnable 1. (a.) Not to be taken by assault; incapable of being subdued; unconquerable; as, an impregnable fortress; impregnable virtue. 2. (a.) Capable of being impregnated, as the egg of an animal, or the ovule of a plant. Thesaurus Entries deathless, defended, guarded, immortal, impenetrable, imperishable, incontestable, incorruptible, indelible, indestructible, indomitable, ineffaceable, ineradicable, inexpugnable, inextinguishable, insuperable, invincible, inviolable, invulnerable, irresistible, mighty, nonperishable, overpowering, overwhelming, protected, quenchless, resistless, safe, safeguarded, secure, shielded, unassailable, unbeatable, unconquerable, undampable, undefeatable, undestroyable, undying, unquenchable, unsubduable, unsurmountable, unyielding |