WordWeb Online

1. Causing or capable of causing harm
   "too much sun is harmful to the skin"; "harmful effects of smoking"

See also: abusive, bad, bruising, calumniatory, calumnious, catastrophic, counterproductive, damaging, defamatory, deleterious, denigrating, denigrative, denigratory, destructive, detrimental, disadvantageous, harmfully, harmfulness, hurtful, ill, injurious, insidious, libellous [Brit, Cdn], libelous [US], malign, mischievous, nocent, noxious, offensive, painful, pernicious, prejudicial, prejudicious, ruinous, slanderous, stabbing, subtle, toxic, unwholesome, wounding

Antonym: harmless

Encyclopedia: Harmful