Del`e·te'ri·ous adjective [ Late Latin deleterius noxious, Greek dhlhth`rios , from dhlei^sqai to hurt, damage; probably akin to Latin delere to destroy.] Hurtful; noxious; destructive; pernicious; as, a deleterious plant or quality; a deleterious ex... Found on http://www.encyclo.co.uk/webster/D/28
deleterious 1. Having a harmful effect; injurious: 'Face it, there is obviously a deleterious effect from smoking.' 2. Having a harmful or damaging effect on someone or something. Found on http://www.wordinfo.info/words/index/info/view_unit/4299/