67 entries under complex topic. ×

26
knotty(adjective, hard, severe, rough, difficult)
26
tricky(adjective, hard, difficult, awkward)
25
dire(adjective, hard, difficult, painful)
25
thorny(adjective, hard, difficult, demanding)
24
serious(adjective, hard, tough, easy, difficult)
24
sheer(adjective, hard, sharp, difficult)
23
grinding(adjective, hard, difficult, harsh, cruel)
22
unbearable(adjective, hard, difficult, painful)
21
ambitious(adjective, hard, ability, difficult)
21
weighty(adjective, hard, difficult, heavy)
20
cruel(adjective, hard, difficult, painful)
20
hefty(adjective, dull, hard, difficult, harsh)
20
intricate(adjective, hard, difficult, awkward)
20
sensitive(adjective, hard, difficult, painful)
19
Gordian(adjective, hard, difficult, intricate)
19
byzantine(adjective, hard, difficult, intricate)
19
elaborate(adjective, hard, difficult, grand)
19
involved(adjective, hard, difficult, awkward)
19
knotted(adjective, hard, difficult)
19
labyrinthine(adjective, hard, difficult, intricate)
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APASmart Define. (2016). arduous thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/arduous/thesaurus/synonyms
ChicagoSmart Define. 2016. "arduous thesaurus" https://smartdefine.org/arduous/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2016, arduous thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/arduous/thesaurus/synonyms>.
MLASmart Define. "arduous thesaurus" 26 February 2016. Web. 20 September 2026. <https://smartdefine.org/arduous/thesaurus/synonyms>