Related Clues:

• Physical faculty
• 'No ___!' ('Of course!')
• Fool's lack
• Dog’s good sense
• What daredevils seem to lack
• Become conscious of
• Use one's head
• Refrigerator or shoe issue
• Not to be believed
• Not trustworthy
• Hearing, for one
• Sound thinking
• Skepticism
• Its shadow is often cast
• 'That little darkroom where negatives are developed,' per Michael Pritchard