Impregnable and Impenetrable

Impregnable

Impregnable adjective - Impossible to get through or into.
Usage example: the castle's supposedly impregnable walls

Impenetrable is a synonym for impregnable in invulnerable topic. In some cases you can use "Impenetrable" instead an adjective "Impregnable", when it comes to topics like property, unyielding, impassible. popular alternative

Impenetrable

Impenetrable adjective - Impossible to get through or into.
Usage example: the ancient temple was surrounded by vast stretches of impenetrable jungle

Impregnable is a synonym for impenetrable in property topic. You can use "Impregnable" instead an adjective "Impenetrable", if it concerns topics such as invulnerable, impassible. popular alternative

Nearby Words: impenetrability, impenetrably
Cite this Source
Impenetrable and Impregnable. (2016). Retrieved 2026, August 16, from https://thesaurus.plus/related/impregnable/impenetrable
Impregnable & Impenetrable. N.p., 2016. Web. 16 Aug. 2026. <https://thesaurus.plus/related/impregnable/impenetrable>.
Impenetrable or Impregnable. 2016. Accessed August 16, 2026. https://thesaurus.plus/related/impregnable/impenetrable.
Google Ngram Viewer shows how "impregnable" and "impenetrable" have occurred on timeline