opt-out noun 3adjective 1opt out verb 1forms 4 noun3 •The act of opting out of something.It [Greenpeace] also says that tax exemptions should be phased out for airlines, including the opt-outs that low-cost carriers currently have from paying VAT or fuel duty on kerosene. — 2023 •A regional broadcast that other stations in the network may elect not to include.National television channels (descendant network) with regional or local slots or opt-outs: […] — 1995 •(UK) A school or hospital that has withdrawn from local control. adjective1 •Requiring a person or organization to choose explicitly to avoid or forbid something; tending to include by default; used particularly with regard to mailing lists and advertising.With opt-out forms, take care to uncheck all unwanted selections. opt out verb1 •To choose not to participate in something. formsopted out · opting out · opts out · opt-outs