2
enigmatic
2
hopeless
2
indivisible
2
irresolvable(adjective, unable, answered)
2
perplexing
2
puzzling
2
unexplainable(adjective, inexplicable)
2
unresolvable
2
unresolved(adjective, unable, answered)
2
unsolved(adjective, unable, answered)
1
abstruse(strange, unknown, curious, concealed, inexplicable)
1
active
1
alchemistic(strange, unknown, curious, concealed, inexplicable)
1
arcane
1
astrological(strange, unknown, curious, concealed, inexplicable)
1
awkward(tough, difficult, wild, obstinate, stubborn)
1
cantankerous(tough, difficult, wild, awkward, obstinate)
1
complicated
1
concealed(strange, unknown, curious, inexplicable, unexplained)
1
contrary(tough, difficult, wild, awkward, obstinate)
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APASmart Define. (2015). insoluble thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/insoluble/thesaurus/synonyms
ChicagoSmart Define. 2015. "insoluble thesaurus" https://smartdefine.org/insoluble/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2015, insoluble thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/insoluble/thesaurus/synonyms>.
MLASmart Define. "insoluble thesaurus" 14 April 2015. Web. 26 September 2026. <https://smartdefine.org/insoluble/thesaurus/synonyms>