7
impervious(adjective, unyielding, unbending, unable, unreceptive)
3
impermeable(adjective, unaffected, unyielding, unbending, resistant)
2
impassable(unaffected, unyielding, unbending, resistant, unreceptive)
2
resistant(unaffected, unyielding, unbending, unreceptive)
1
greaseproof
1
ladder-proof
1
moth-resistant
1
mothproof
1
proof
1
run-resistant
1
runproof
1
soundproof
0
acid-fast
0
closed to(expression, unaffected, unyielding, unbending, resistant)
0
colorfast
0
corrosion-resistant
0
fast
0
hermetic(unaffected, unyielding, unbending, resistant, unreceptive)
0
immune(unaffected, unyielding, unbending, resistant, unreceptive)
0
impassive(unaffected, unyielding, unbending, resistant, unreceptive)
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APASmart Define. (2013). imperviable thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/imperviable/thesaurus/synonyms
ChicagoSmart Define. 2013. "imperviable thesaurus" https://smartdefine.org/imperviable/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2013, imperviable thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/imperviable/thesaurus/synonyms>.
MLASmart Define. "imperviable thesaurus" 28 June 2013. Web. 21 September 2026. <https://smartdefine.org/imperviable/thesaurus/synonyms>