impenetrable
im·pe·net·rable
adjective
1.
not admitting of penetration or passage into or through
- “an impenetrable fortress”
- “impenetrable rain forests”
2.
3.
Origin
From Middle English inpenetrabel, inpenetrabyle, from Middle French impenetrable or directly from its etymon, Latin impenetrābilis. By surface analysis, im- + penetrable.
Related words
Word family
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). CMU Pronouncing Dictionary. WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.