deleterious
adjective
UK/ˌdel.ɪˈtɪə.ri.əs/
US/ˌdel.ɪˈtɪr.i.əs/
Definitions of deleterious adjective
Causing harm or damage.
Prolonged exposure to intense sunlight can have a deleterious effect on the skin.
Research indicates that this chemical has a significant deleterious impact on the environment.
Excessive sugar in one's diet can be deleterious to overall health.