Bible Dictionaries
Impregnable

Webster's Dictionary

(1):

(a.) Not to be stormed, or taken by assault; incapable of being subdued; able to resist attack; 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.

Bibliography Information
Webster, Noah. Entry for 'Impregnable'. Noah Webster's American Dictionary. https://www.studylight.org/​dictionaries/​eng/​web/​i/impregnable.html. 1828.