Related Clues:

• Direct-mail response sticker
• Green light
• 'That's it!'
• Cry of success
• Positive
• Aye-aye
• 'You betcha!'
• Sanction
• Proposal response
• Toady's response
• Irrefutable
• 'Indubitably'
• See 58-Down
• '___, right!'
• Part of a Beatles refrain