Related Clues:

• Affirmative action?
• Wooden shoe passenger
• Silent bid
• Unspoken assent
• Pal of Wynken and Blynken
• Positive sign
• Silent OK
• Head movement
• Endorsement
• Silent assent
• Positive response
• 'Uh-huh' equivalent
• Affirmation
• Agree, in a way
• Doze off