Chilling Effect

A chilling effect is a situation where speech or conduct is suppressed or limited by fear of penalization at the hands of an individual or group. For example, the threat of a costly and lengthy lawsuit might prompt self-censorship and have a chilling effect on free speech. Since many such suits rely on libel law, the term libel chill is also often used.
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The lowering of the Earth's temperature because of increased particles in the air blocking the sun's rays. (See: greenhouse effect.)