- 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
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for impenetrably
“In this country that we were told was impenetrably dangerous, guys were just turning up,” he said.Iraq, Under the Boot
October 15, 2009
The rushlight had burned out and the cell was impenetrably dark.Micah Clarke
Arthur Conan Doyle
"Till nine o'clock or a little after," suggested Mrs. Travers, impenetrably.The Rescue
But Wilkins was as impenetrably suave as he had been the day before.The Search Party
G. A. Birmingham
It was a cold, rainy, and impenetrably dark night on the tow-path.A Tale of the Tow-Path
The choir is impenetrably dark most of the year at this early hour.
- 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
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 impenetrably
Online Etymology Dictionary, © 2010 Douglas Harper