3
bad to the bone
3
counterproductive
3
cruel(unkind, upsetting, fatal, poisonous, lethal)
3
disserviceable
3
hateful(adjective, person, unfriendly)
3
incendiary(adjective, injurious, damaging, destructive, hurtful)
3
inopportune(adjective, damaging, disparaging, hurtful, detrimental)
3
internecine(adjective, violent, cruel, injurious, damaging)
3
invidious
3
morbific
3
mortal(adjective, bad, evil, dangerous, injurious)
3
nefarious(bad, corrupt, immoral, sinful, injurious)
3
precarious(adjective, risky, dangerous, unsafe)
3
scathing
3
septic
3
serious(adjective, bad, offensive, foul, revolting)
3
subversive(adjective, injurious, damaging, destructive, hurtful)
3
undesireworthy(adjective, arouse bad feelings, arouse bad emotions)
2
afflicting
2
annihilative(adjective, injurious, damaging, deadly, fatal)
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APASmart Define. (2016). harmful thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/harmful/thesaurus/synonyms
ChicagoSmart Define. 2016. "harmful thesaurus" https://smartdefine.org/harmful/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2016, harmful thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/harmful/thesaurus/synonyms>.
MLASmart Define. "harmful thesaurus" 24 March 2016. Web. 24 September 2026. <https://smartdefine.org/harmful/thesaurus/synonyms>