Related Clues:

• Well-balanced
• Sound in the head
• Lucid
• Unflappable
• Has enough marbles
• Right-minded
• Laid-back
• Playing will a full deck, so to speak
• Capable of thinking clearly
• Not out of one's mind
• Clear-headed
• Dignified
• Not nuts
• Perfectly reasonable
• Opposite of 53-Down