producing or tending to produce infectious or contagious, often epidemic, disease; pestilential.

destructive to life; deadly; poisonous.

injurious to peace, morals, etc.; pernicious.

troublesome, annoying, or mischievous.

adjective

baneful , contagious , contaminating , corrupting , deadly , deleterious , destructive , detrimental , diseased , evil , fatal , harmful , infectious , injurious , lethal , mortal , noxious , pernicious , pestiferous , pestilential , ruinous , tainting , troublesome , vicious , malignant , dangerous