Related Clues:

• Sound upstairs
• Of sound mind
• Cool and collected
• Commonsensical
• Fit to be tried
• Unlikely to be committed
• Clear-thinking
• Well-balanced
• Sound in the head
• Lucid
• Has enough marbles
• Right-minded
• Playing will a full deck, so to speak
• Capable of thinking clearly
• Not out of one's mind