Synonyms for impregnable

Similarity of adj impregnable

3 senses of impregnable

Sense 1:

impregnable, inviolable, secure, strong, unassailable, unattackable
invulnerable (vs. vulnerable)

Sense 2:

conceptive, impregnable
fertile (vs. sterile)

Sense 3:

impregnable, inexpugnable
unconquerable (vs. conquerable)