pestiferous (adj.)
- aggravating
- annoying
- bad
- baneful
- bothersome
- catching
- communicable
- contagious
- contaminated
- deadly
- destructive
- disturbing
- endemic
- epidemic
- epiphytotic
- epizootic
- exasperating
- foul
- galling
- harmful
- importunate
- infectious
- infective
- injurious
- insalubrious
- insanitary
- irksome
- irritating
- malign
- malignant
- mephitic
- miasmal
- miasmic
- morbific
- noisome
- noxious
- pandemic
- pathogenic
- peccant
- pesky
- pestering
- pestilent
- pestilential
- plaguey
- poisonous
- polluted
- provoking
- septic
- sporadic
- tainted
- taking
- teasing
- tiresome
- toxic
- toxicant
- troublesome
- troubling
- unhealthful
- unhealthy
- unhygienic
- unsanitary
- unwholesome
- venomous
- vexatious
- vexing
- virulent
- wearisome
- worrisome
- worrying
- zymotic
