Impregnable
Impregnable adjective - Incapable of being defeated, overcome, or subdued.
Locked and impregnable are semantically related. In some cases you can use "Locked" instead an adjective "Impregnable".
Locked
Impregnable and locked are semantically related. Sometimes you can use "Impregnable" instead an adjective "Locked".
Mutual synonyms
Both words in one sentence
- Instead they plan to steal the prize, which is locked inside an impregnable vault: two burned chunks of an exploded star cruiser, one of which may hold the key to the wealth of an entire world.But the truth about the treasure is dangerous and deadly.
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Locked Room Mystery: A near-literal example occurs as a subplot in Shrinking House, where the boys have to figure out how someone has been getting in and out of an impregnable concrete art studio with only one locked door in order to move Joshua Cameron's paintings.
Cite this Source
Locked and Impregnable. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/impregnable/locked
Impregnable & Locked. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/impregnable/locked>.
Locked or Impregnable. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/impregnable/locked.
Google Ngram Viewer shows how "impregnable" and "locked" have occurred on timeline