Impregnability :: Impregnability (n.) The quality or state of being impregnable; invincibility.
Impregnable :: Impregnable (a.) Not to be stormed, or taken by assault; incapable of being subdued; able to resist attack; unconquerable; as, an impregnable fortress; impregnable virtue..
Impregnable :: Impregnable (a.) Capable of being impregnated, as the egg of an animal, or the ovule of a plant..
Pregnable :: Pregnable (a.) Capable of being entered, taken, or captured; expugnable; as, a pregnable fort..