opt-out

Short definition from Wiktionary

Adjective

1. 1
   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.

Noun

1. 1
   The act of opting out of something.
2. 2
   A school or hospital that has withdrawn from local control.
3. 3
   A regional broadcast that other stations in the network may elect not to include.

Verb

1. 1
   To choose not to participate in something.