Impenetrable
Impenetrable adjective - Impossible to get through or into.
Nearby Words: impenetrability, impenetrably
Thin
Thin adjective - Relatively thin in consistency or low in density; not viscous.
Usage example: thin oil
Impenetrable is an antonym for thin.
Both words in one sentence
- Good writers find tougher problems (impenetrable force-fields, not knowing where the bomb is, things that require flight, ice rinks, high-altitude air too thin to support their metabolism, etc.).
Source: Useless Superpowers - Cross-dressing of one sort or another, usually in the form of Paper Thin Disguises which are usually damn near impenetrable.
Source: Once per Episode -
Due to engine limitations, all materials are either breakable (like glass) or completely impenetrable (although one can shoot through doors or very thin walls, if the target stands right next to it).
Source: Video Game / Urban Terror
Cite this Source
Thin and Impenetrable. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/impenetrable/thin
Impenetrable & Thin. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/impenetrable/thin>.
Thin or Impenetrable. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/impenetrable/thin.
Google Ngram Viewer shows how "impenetrable" and "thin" have occurred on timeline