- Not to be stormed, or taken by assault; incapable of
being subdued; able to resist attack; unconquerable; as, an impregnable
fortress; impregnable virtue. - Capable of being impregnated, as the egg of an animal,
or the ovule of a plant.
Meaning of 'impregnable' (Princeton's WordNet)
1 . impregnable
[ s]
Meaning (1): - immune to attack; incapable of being tampered with
Example in sentence:
a secure telephone connection;
an impregnable fortress;
fortifications that made the frontier inviolable
Meaning (2): - incapable of being overcome, challenged or refuted