1. (a.) Pest-bearing; pestilential; noxious to health; malignant; infectious; contagious; as, pestiferous bodies.

2. (a.) Noxious to peace, to morals, or to society; vicious; hurtful; destructive; as, a pestiferous demagogue.

aggravating annoying bad bad for baneful bothering bothersome catching communicable contagious contaminated deadly destructive disturbing endemic envenomed epidemial epidemic epiphytotic epizootic exasperating foul galling harassing harmful importunate importune infectious infective injurious inoculable insalubrious insanitary irking irksome irritating malign malignant mephitic miasmal miasmatic miasmic morbific noisome noxious pandemic pathogenic peccant pesky pestering pestilent pestilential plaguesome plaguey plaguing poisonous polluted provoking septic sporadic spreading tainted taking teasing tiresome tormenting toxic toxicant toxiferous troublesome troubling unhealthful unhealthy unhygienic unsanitary unwholesome venenate veneniferous venenous venomous vexatious vexing virulent wearisome worrisome worrying zymotic