toxic
/ˈtɒk.sɪk/
Having a chemical nature that is harmful to health or lethal if consumed or otherwise entering into the body in sufficient quantities.
Tobacco smoke contains many toxic substances.
Appearing grossly unwell; characterised by serious, potentially life-threatening compromise in the respiratory, circulatory or other body systems.
The child appeared toxic on arrival at the hospital.
Severely negative or harmful.
a toxic environment that promoted bullying
(of a person) Hateful or strongly antipathetic.
It is not good to be around toxic people.