toxic - of or relating to or caused by a toxin or poison; "suffering from exposure to toxic substances"harmful - causing or capable of causing harm; "too much sun is harmful to the skin"; "harmful effects of smoking" unhealthful - detrimental to good health; "unhealthful air pollution"; "unhealthful conditions in old apartments with peeling lead-based paint" harmful, noxious - injurious to physical or mental health; "noxious chemical wastes"; "noxious ideas" |