7
vexing
6
infectious(adjective, annoying)
6
insalubrious(offensive, foul, disgusting, harmful, poisonous)
6
plaguy
6
poisonous(adjective, bad, offensive, foul, disgusting)
6
unhealthy(adjective, offensive, foul, disgusting, injurious)
5
contaminated
5
contagious(adjective, annoying, communicable)
5
damaging(adjective, bad, harmful, injurious, deadly)
5
injurious(adjective, bad, foul, vile, harmful)
5
irksome
5
obnoxious(adjective, nasty, offensive, terrible, foul)
5
troublesome(adjective, bothersome, worrisome)
5
virulent(adjective, unhealthy, injurious, annoying, fatal)
4
aggravating
4
corruptive
4
deadly(adjective, bad, evil, harmful, injurious)
4
dirty
4
exasperating
4
perversive
11 years ago|8.5k views|share |citing 
APASmart Define. (2015). pestiferous thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/pestiferous/thesaurus/synonyms
ChicagoSmart Define. 2015. "pestiferous thesaurus" https://smartdefine.org/pestiferous/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2015, pestiferous thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/pestiferous/thesaurus/synonyms>.
MLASmart Define. "pestiferous thesaurus" 10 April 2015. Web. 26 September 2026. <https://smartdefine.org/pestiferous/thesaurus/synonyms>