134 entries under difficult topic. ×

1
diligent(adjective, tedious, protracted)
1
entangled(adjective, hard, fancy, complex)
1
fancy(adjective, hard, complex, intricate)
1
gasser(adjective, hard, fancy, complex)
1
hellish(adjective, unpleasant, grim, savage)
1
hi-tech(adjective, hard, fancy, complex)
1
interlaced(adjective, hard, fancy, complex)
1
mega factor(expression, adjective, hard, fancy)
1
merciless(adjective, tough, severe, rough)
1
mixed(adjective, hard, fancy, complex)
1
murder(adjective, hard, great, tough, severe)
1
nagging(adjective, hard, tough, painful)
1
perplexing(adjective, hard, fancy, severe)
1
puzzling(adjective, hard, fancy, severe)
1
recondite(adjective, hard, fancy, complex)
1
rigid(adjective, hard, tough, severe, rough)
1
sapping(adjective, unpleasant, grim, savage)
1
strict(adjective, hard, tough, severe, rough)
1
testing(adjective, tough, severe, violent)
1
unsparing(adjective, tough, rough, harsh)
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APASmart Define. (2016). arduous thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/arduous/thesaurus/synonyms
ChicagoSmart Define. 2016. "arduous thesaurus" https://smartdefine.org/arduous/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2016, arduous thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/arduous/thesaurus/synonyms>.
MLASmart Define. "arduous thesaurus" 26 February 2016. Web. 21 September 2026. <https://smartdefine.org/arduous/thesaurus/synonyms>