Noun
ill effect (plural ill effects)
(Often plural) A detrimental or harmful effect.
ill-effect
All we need is a meteorologist who has once been soaked to the skin without ill effect. No one can write knowingly of the weather who walks bent over on wet days. E. B. White
The little may contrast with the great, in painting, but cannot be said to be contrary to it. Oppositions of colors contrast; but there are also colors contrary to each other, that is, which produce an ill effect because they shock the eye when brought very near it. Voltaire