140 entries under complex topic. ×

18
messy(adjective, hard, difficult)
18
multiple(adjective, hard, difficult)
18
precarious(adjective, hard, difficult)
18
sensitive(adjective, hard, difficult, delicate)
18
severe(adjective, hard, difficult, awkward)
18
sinuous(adjective, hard, difficult)
18
toilsome(adjective, hard, difficult, awkward)
18
trying(adjective, hard, difficult, thorny)
14
convoluted(adjective, hard, simple, fancy, obscure)
14
entangled(verb, adjective, hard, fancy, difficult)
11
confused(verb, adjective, obscure, sophisticated)
10
tortuous(adjective, obscure, difficult, sophisticated)
8
abstruse(adjective, hard, fancy, obscure, difficult)
8
obscure(adjective, hard, difficult, sophisticated)
8
perplexing(adjective, hard, fancy, obscure, difficult)
6
deep(adjective, hard, obscure, full)
6
puzzling(adjective, hard, fancy, obscure, difficult)
5
confusing(adjective, hard, tricky, complicated)
5
recondite(adjective, hard, fancy, obscure, difficult)
4
baffling(adjective, hard, difficult, awkward)
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APASmart Define. (2015). involved thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/involved/thesaurus/synonyms
ChicagoSmart Define. 2015. "involved thesaurus" https://smartdefine.org/involved/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, involved thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/involved/thesaurus/synonyms>.
MLASmart Define. "involved thesaurus" 14 April 2015. Web. 20 September 2026. <https://smartdefine.org/involved/thesaurus/synonyms>