Related Clues:

• Fall asleep (with "off")
• Agree wordlessly
• Signal of approval
• Put one's hands together, in a way
• Drowse
• Bobbleheads do it
• Approval of a sort
• Subtle assent
• Assent wordlessly
• Head-moving assent
• Thunder
• Nomination, so to speak
• Say "yes" without saying it
• Bid silently
• Make some noise