impenetrable

[im-pen-i-truh-buhl]

See more synonyms for impenetrable on Thesaurus.com

adjective

not penetrable; that cannot be penetrated, pierced, entered, etc.
inaccessible to ideas, influences, etc.
incapable of being understood; inscrutable; unfathomable: an impenetrable mystery.

Physics. possessing impenetrability.

Origin of impenetrable

1425–75; late Middle English impenetrabel < Latin impenetrābilis. See im-², penetrable

Related formsim·pen·e·tra·ble·ness, nounim·pen·e·tra·bly, adverb

Synonyms for impenetrable

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3. incomprehensible, mysterious, obscure, hidden.

Antonyms for impenetrable

3. clear, lucid.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for impenetrable

impervious, impassable, bulletproof, unintelligible, unfathomable, baffling, unaccountable, arcane, inexplicable, inscrutable, mysterious, close, compact, firm, hard, hermetic, impermeable, inviolable, solid, substantial

Examples from the Web for impenetrable

Contemporary Examples of impenetrable

At the highest navigable point of the Congo River, thick jungle creates an impenetrable wall of green around a large island.
The Congo's Forgotten Colonial Getaway
Nina Strochlic
December 18, 2014
These reporters are working within a bubble, impenetrable to secular outsiders.
Who Gagged the Search for MH370?
Clive Irving
June 22, 2014
But, as Korda clearly recognizes, Lee himself could be almost as impenetrable as stone.
How I Learned to Hate Robert E. Lee
Christopher Dickey
June 22, 2014
The Brazilian defense, touted as impenetrable in pre-tournament hype, proved to be bedraggled, and porous.
Brazil Slips Past Croatia, Thanks to Yuichi Nishimura
Tunku Varadarajan
June 12, 2014
He had two hits for three official at-bats; yet afterward his solitary gloom was impenetrable.
Murray Kempton on The Homecoming of Willie Mays
Murray Kempton
March 31, 2014

Historical Examples of impenetrable

“An impenetrable mystery” was sure “to hang for ever” as far as all mankind was concerned.
The Secret Agent
Joseph Conrad
Kirkwood smiled grimly, with a face of brass, impenetrable, inflexible.
The Black Bag
Louis Joseph Vance
Go not to the Alhambra: the fort is impenetrable—the guard faithful.
Leila, Complete
Edward Bulwer-Lytton
He had been prepared for abuse, but not for impenetrable silence.
One Day's Courtship
Robert Barr
Since then Tawabinisy had hidden himself behind his impenetrable grin.
The Forest
Stewart Edward White

British Dictionary definitions for impenetrable

impenetrable

adjective

incapable of being pierced through or penetratedan impenetrable forest
incapable of being understood; incomprehensibleimpenetrable jargon
incapable of being seen throughimpenetrable gloom
not susceptible to ideas, influence, etcimpenetrable ignorance
physics (of a body) incapable of occupying the same space as another body

Derived Formsimpenetrability, nounimpenetrableness, nounimpenetrably, adverb

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for impenetrable

adj.

mid-15c., from Middle French impenetrable, from Latin impenetrabilis "that cannot be penetrated," from assimilated form of in- "not, opposite of" (see in- (1)) + penetrabilis "penetrable" (see penetrate). Related: Impenetrably; impenetrability.