2
baleful(adjective, bad, evil, harmful, injurious)
2
disagreeable(nasty, unpleasant, horrible, hateful, loathsome)
2
epidemic
2
foul(adjective, bad, nasty, offensive, terrible)
2
fractious
2
harassing(injurious, damaging, destructive, disorderly, unruly)
2
hateful(adjective, nasty, offensive, terrible, disgusting)
2
hurtful(adjective, bad, evil, harmful, injurious)
2
infected
2
inimical(injurious, damaging, destructive)
2
irritable
2
lethal(adjective, bad, evil, harmful, injurious)
2
malign(adjective, bad, evil, nasty, terrible)
2
mischievous(offensive, foul, disgusting, injurious, damaging)
2
morbific
2
mortal(adjective, bad, evil, harmful, injurious)
2
petulant
2
septic
2
tiresome
2
toxicant(adjective, poisonous)
11 years ago|8.5k views|share |citing 
APASmart Define. (2015). pestiferous thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/pestiferous/thesaurus/synonyms
ChicagoSmart Define. 2015. "pestiferous thesaurus" https://smartdefine.org/pestiferous/thesaurus/synonyms (accessed September 27, 2026).
HarvardSmart Define 2015, pestiferous thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/pestiferous/thesaurus/synonyms>.
MLASmart Define. "pestiferous thesaurus" 10 April 2015. Web. 27 September 2026. <https://smartdefine.org/pestiferous/thesaurus/synonyms>