detrimental
/ˌde-trə-ˈmen-tᵊl/
adjective
obviously harmful : damaging
the detrimental effects of pollution
pernicious baneful noxious deleterious detrimental mean exceedingly harmful. pernicious implies irreparable harm done through evil or insidious corrupting or undermining. baneful implies injury through poisoning or destroying.
noun
an undesirable or harmful person or thing