1
as in dense
impossible to get through or into
the ancient temple was surrounded by vast stretches of impenetrable jungle
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2
as in mysterious
being beyond one's powers to know, understand, or explain
the mysteries of that religion are completely impenetrable to outsiders
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3
as in incomprehensible
impossible to understand
the textbook's language is completely impenetrable, at least to me
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4
as in tight
not allowing penetration (as by gas, liquid, or light)
the container of toxic waste has an impenetrable seal to prevent leaks
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Example Sentences
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Recent Examples of impenetrable
Surrounded by highly skilled bodyguards, Safra had created a haven in Monaco in the form of an impenetrable penthouse apartment, equipped with state-of-the-art security systems.
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Alex Gurley, PEOPLE, 21 Dec. 2025
Tech leaders’ business success and wealth, inflated by years of near-zero interest rates, fed an impenetrable faith in their own exceptionalism.
—Foreign Affairs, 16 Dec. 2025
Shopping deals and savory recipes were interspersed between updates on the growing second World War and analysis about the United States’ impenetrable defensibility.
—Angele Latham, Nashville Tennessean, 7 Dec. 2025
Bradley has an airiness about her—an impenetrable light source that maintains positivity through strife.
—Malik Peay, Essence, 4 Dec. 2025
See All Example Sentences for impenetrable
Recent Examples of Synonyms for impenetrable
Adjective
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In extremely dense fog where visibility is near zero, the best course of action is to first turn on your hazard lights, then simply pull into a safe location such as a parking lot of a local business, and stop.—
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At 6-foot-3, 275 pounds, Bain’s measurables might not fit every team’s wish list but would work well in Kansas City, where defensive coordinator Steve Spagnuolo has preferred dense and powerful pass rushers.—
Adjective
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Not to mention the titular bugs, a swarm of blood-invading creatures discovered by her new lover, the mysterious drifter Peter Evans (Namir Smallwood).—
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The Columbus, Ohio, police chief is speaking out for the first time since the mysterious murders of dentist Spencer Tepe and his wife, Monique Tepe.—
Adjective
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The scope of the effort is almost incomprehensible, both for its sheer size and persistence on a low-lying peninsula, where the delineation between land and sea has always been somewhat unclear and is becoming less so.—
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In these cases, the equations will predict a fluid moving in some unphysical, incomprehensible way — spinning into an impossibly fast vortex, for instance, or instantly reversing its flow.—
Adjective
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Loveland caught eight passes for 137 yards for the Bears, who had closed the regular season with tight losses to San Francisco and Detroit.—
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As temperatures drop and humidity plummets, the skin’s natural moisture levels decline faster, fine lines look more pronounced, and that tight, uncomfortable feeling can become a near-daily occurrence.—
Adjective
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Trump, however, is impervious to legal restraints.—
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Rates for commercial and industrial properties will be increased based on impervious surface and square footage.—
Adjective
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By contrast, fringe subcultures operate in a more cryptic and chaotic manner.—
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Heeding these cryptic words some three decades later, the audacious (and well-read) impresario Tony Wilson opened the Haçienda together with the circle of post-punk musicians and designers involved with his label, Factory Records.—
Adjective
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As satire, Next to Heaven is unintelligible, as though someone is universalizing their own hangups and then skewering them for clout.—
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A number of individuals who were in that classroom told authorities that the gunman shouted an unintelligible statement and then began shooting students.—
Adjective
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The impermeable seed coat strategy generally helps survival of the species by making sure all of a season’s crop don’t germinate in the same year.—
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The discovery could enable large-scale use of impermeable coatings once limited by graphene’s scalability issues.—
Cite this Entry
“Impenetrable.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/impenetrable. Accessed 13 Jan. 2026.
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