an annoying or troublesome person, animal, or thing; nuisance.

an insect or other small animal that harms or destroys garden plants, trees, etc.

a deadly epidemic disease, esp. a plague; pestilence.

noun

annoyance , badgerer , bane , besetment , blight , blister , bore , bother , botheration , bug * , contagion , crashing bore , creep , curse , drag , drip , epidemic , exasperation , headache * , infection , irritant , irritation , nag , nudge , nuisance , pain * , pain in the neck * , pesterer , pestilence , pill * , plague * , scourge * , tease * , thorn in side , tormentor , trial * , trouble , vexation , virus * , bug , gnat , heckler , infliction , insect , louse , plague , scourge , vermin