4
inimical(adjective, mean, nasty, offensive, cold)
4
internecine(adjective, injurious, damaging, destructive, fatal)
4
maleficent(adjective, malevolence)
4
noisome(adjective, inexpedience)
4
ruinous(adjective, bad, injurious, damaging, deadly)
4
septic(adjective, unhealthy)
4
treacherous(adjective, dangerous, malevolent)
4
unhealthy(adjective, bad, offensive, heavy, foul)
3
acerbic
3
bad to the bone
3
catty(adjective, mean, nasty, vicious, wicked)
3
corrosive(adjective, malevolent)
3
corrupt
3
deathly(adjective, dangerous)
3
diabolic
3
diseased(adjective, unhealthy, spreading, cancerous)
3
disserviceable
3
disturbing(adjective, arouse bad feelings)
3
envenomed
3
ill-natured(adjective, mean, malicious, malevolent, vindictive)
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APASmart Define. (2016). malignant thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/malignant/thesaurus/synonyms
ChicagoSmart Define. 2016. "malignant thesaurus" https://smartdefine.org/malignant/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2016, malignant thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/malignant/thesaurus/synonyms>.
MLASmart Define. "malignant thesaurus" 24 March 2016. Web. 21 September 2026. <https://smartdefine.org/malignant/thesaurus/synonyms>