19 entries under impossibility topic. ×

16
insurmountable(adjective, do, impossible, impassable)
10
impassable(adjective, do, indomitable)
8
unsurmountable
2
impervious
2
inextricable
2
unattainable
2
unfeasible
1
hopeless
1
desperate
1
inaccessible
1
incompatible
1
infeasible
1
out of reach(expression, idiom)
1
self-contradictory
1
unobtainable
0
beyond control(expression, idiom)
0
impracticable unachievable(expression, idiom)
0
innavigable
0
uncomeatable
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APASmart Define. (2015). insuperable thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/insuperable/thesaurus/synonyms
ChicagoSmart Define. 2015. "insuperable thesaurus" https://smartdefine.org/insuperable/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2015, insuperable thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/insuperable/thesaurus/synonyms>.
MLASmart Define. "insuperable thesaurus" 14 April 2015. Web. 23 September 2026. <https://smartdefine.org/insuperable/thesaurus/synonyms>