Related Clues:

• Annul
• Rescind
• Nix
• Negate
• Scrub, as a mission
• Stop some e-mail
• Decline to participate
• ATM button
• Choose not to participate
• Decide not to participate
• Option on an online order form
• Decide to quit
• End, as a subscription
• A.T.M. button
• Choose not to receive ads by email, e.g.