8
vulnerable
7
penetrable(adjective, clear, open, watertight, enigmatical)
5
permeable
4
clairvoyant
4
comprehensible
4
intelligible
4
passable
4
thin
4
understandable
4
clear
3
porous
3
soft
2
obvious
2
pervious
2
self-explanatory(adjective, obvious)
2
transparent
1
apparent
1
comprehendible
1
discernible
1
easy
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APASmart Define. (2015). impenetrable thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/impenetrable/thesaurus/antonyms
ChicagoSmart Define. 2015. "impenetrable thesaurus" https://smartdefine.org/impenetrable/thesaurus/antonyms (accessed September 23, 2026).
HarvardSmart Define 2015, impenetrable thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/impenetrable/thesaurus/antonyms>.
MLASmart Define. "impenetrable thesaurus" 10 April 2015. Web. 23 September 2026. <https://smartdefine.org/impenetrable/thesaurus/antonyms>