Related Clues:

• Emulated Rip Van Winkle
• Signaled 'yes'
• Recharged, say
• Took an 81 Across
• Took a catnap
• Signalled affirmation
• Showed assent
• Caught some z’s
• Enjoyed a boring lecture?
• Wasn’t vigilant
• Signaled agreement
• Didn't pull an all-nighter
• Took a nap, say
• Got some rack time
• Had a great night's rest