5
demanding
5
difficult(adjective, hard, trivial, nice)
4
effortful
4
hard
4
laborious(adjective, hard, difficult, facile)
3
heavy
3
labored
2
backbreaking
2
arduous
2
burdensome
2
complicated
2
formidable
2
grueling
2
laboured
2
leaden
2
murderous
2
onerous
2
problematic
2
punishing
2
severe
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APASmart Define. (2015). effortless thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/effortless/thesaurus/antonyms
ChicagoSmart Define. 2015. "effortless thesaurus" https://smartdefine.org/effortless/thesaurus/antonyms (accessed September 22, 2026).
HarvardSmart Define 2015, effortless thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/effortless/thesaurus/antonyms>.
MLASmart Define. "effortless thesaurus" 10 April 2015. Web. 22 September 2026. <https://smartdefine.org/effortless/thesaurus/antonyms>