impenetrable

[ im-pen-i-truh-buhl ]

adjective

1. not penetrable; that cannot be penetrated, pierced, entered, etc.
2. inaccessible to ideas, influences, etc.
3. incapable of being understood; inscrutable; unfathomable:

   an impenetrable mystery.

   Synonyms: hidden, obscure, mysterious, incomprehensible

   Antonyms: lucid, clear

4. Physics. possessing impenetrability.

impenetrable

/ ɪmˈpɛnɪtrəbəl /

adjective

1. incapable of being pierced through or penetrated

   an impenetrable forest

2. incapable of being understood; incomprehensible

   impenetrable jargon

3. incapable of being seen through

   impenetrable gloom

4. not susceptible to ideas, influence, etc

   impenetrable ignorance

5. physics (of a body) incapable of occupying the same space as another body

Derived Forms

• imˈpenetrableness, noun
• imˌpenetraˈbility, noun
• imˈpenetrably, adverb

Other Words From

• im·pene·tra·ble·ness noun
• im·pene·tra·bly adverb

Word History and Origins

Origin of impenetrable¹

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

Example Sentences

South Korea’s frontier with the North is an almost impenetrable barrier, the heavily mined and fortified Demilitarized Zone.

From BBC

Suriname has some of the most impenetrable jungle in the world, covering 93% of the country.

From BBC

This so-called iron wall had long been viewed by the IDF and people across Israel as impenetrable, and yet bases along it began reporting breaches.

From BBC

The woodland environment - dense thicket and brambles - made it "impenetrable" to zoo volunteers.

From BBC

But Mr. Trump himself, a candidate of unusual personality and sometimes impenetrable psyche, seemed to be willing himself forward, moving from downcast to defiant within a day.

From New York Times

Related Words

• arcane
• baffling
• inexplicable
• inscrutable
• mysterious
• unaccountable
• unfathomable
• unintelligible