3
virulent(adjective, injurious, damaging, destructive, fatal)
2
brutal
2
calamitous(adjective, harmful, injurious, damaging, deadly)
2
cataclysmic(adjective, harmful, injurious, damaging, deadly)
2
consumptive(adjective, bad, painful, harmful, injurious)
2
detrimental(adjective, bad, painful, harmful, injurious)
2
disastrous(adjective, harmful, injurious, damaging, deadly)
2
feral
2
fratricidal
2
homicidal
2
malign
2
mutually ruinous(expression, adjective, idiom)
2
ruinous(adjective, harmful, injurious, damaging, deadly)
2
subversive(injurious, damaging, destructive)
1
annihilative(adjective, harmful, injurious, damaging, deadly)
1
bad(adjective, injurious, damaging, destructive)
1
baleful(adjective, violent, cruel, harmful, injurious)
1
cancerous(adjective, harmful, injurious, damaging, deadly)
1
cataclysmal
1
chivalrous
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APASmart Define. (2015). internecine thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/internecine/thesaurus/synonyms
ChicagoSmart Define. 2015. "internecine thesaurus" https://smartdefine.org/internecine/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, internecine thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/internecine/thesaurus/synonyms>.
MLASmart Define. "internecine thesaurus" 10 April 2015. Web. 22 September 2026. <https://smartdefine.org/internecine/thesaurus/synonyms>