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

Other Word Forms

• impenetrableness noun
• impenetrably adverb
• impenetrability noun

Word History and Origins

Origin of impenetrable¹

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

Related Words

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