6
laboriously(adverb, difficultly)
6
severely(adverb, difficultly)
4
arduously(adverb, difficultly)
4
heavily
3
difficultly(adverb, difficultly)
3
formidably(adverb, difficultly)
3
hardly
3
oppressively(adverb, difficultly)
3
toughly(adverb, difficultly)
3
troublesomely(adverb, difficultly)
2
burdensomely
2
cumbersomely
2
demandingly(adverb, difficultly)
2
grievously
2
grindingly(adverb, difficultly)
2
harshly(adverb, difficultly)
2
onerous
2
roughly(adverb, difficultly)
2
strenuously(adverb, difficultly)
2
toilsomely(adverb, difficultly)
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APASmart Define. (2015). onerously thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/onerously/thesaurus/synonyms
ChicagoSmart Define. 2015. "onerously thesaurus" https://smartdefine.org/onerously/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, onerously thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/onerously/thesaurus/synonyms>.
MLASmart Define. "onerously thesaurus" 14 April 2015. Web. 20 September 2026. <https://smartdefine.org/onerously/thesaurus/synonyms>