Synonyms, Grades 11–12: Harmful

Learn this list of synonyms for harmful.
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Full list of words from this list:

words only definitions & notes
  1. pernicious
    exceedingly harmful
  2. detrimental
    causing harm or injury
  3. pestilent
    exceedingly harmful
  4. baneful
    exceedingly harmful or destructive
  5. noxious
    injurious to physical or mental health
  6. adverse
    contrary to your interests or welfare
  7. injurious
    harmful to living things
  8. deleterious
    harmful to living things
  9. maleficent
    harmful or evil in intent or effect
  10. prejudicial
    tending to cause harm or injury
  11. lethal
    of an instrument of certain death
  12. infectious
    relating to the invasion of germs that cause disease
  13. inimical
    tending to obstruct or cause harm
  14. venomous
    marked by deep ill will; deliberately harmful
  15. fatal
    having extremely unfortunate or dire consequences
  16. insidious
    working or spreading in a hidden and usually injurious way
  17. ruinous
    extremely harmful; bringing catastrophe
  18. catastrophic
    extremely harmful; bringing physical or financial ruin
  19. pestilential
    likely to spread and cause an epidemic disease
  20. destructive
    causing damage
  21. nocent
    having a tendency to cause harm
  22. devastating
    wreaking or capable of wreaking complete destruction
  23. counterproductive
    tending to hinder the achievement of a goal
  24. calamitous
    having extremely unfortunate or dire consequences
  25. cancerous
    spreading or growing in an evil or unpleasant way
  26. cataclysmic
    severely destructive
  27. disastrous
    having extremely unfortunate or dire consequences
  28. malignant
    dangerous to health
  29. prejudicious
    (sometimes followed by `to') causing harm or injury
  30. corrosive
    capable of destroying or eating away by chemical action
Created on Thu Feb 26 12:50:25 EST 2026 (updated Thu Feb 26 12:55:28 EST 2026)

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