Webster's Revised Unabridged Dictionary · 1913

Deleterious

Deleterious , adjective

[Late Latin deleterius noxious, Greek dhlhth`rios, from dhlei^sqai to hurt, damage; prob. akin to Latin delere to destroy.]

Hurtful; noxious; destructive; pernicious; as, a deleterious plant or quality; a deleterious example.