Related Clues:

• Unwilling to budge
• Not subject to bargaining
• Clandestine
• Like some mattresses
• John Grisham novel, with "The"
• Skeleton, so to speak
• Not generally known
• Something confidential
• Unknown to many
• Confidential
• Type of admirer
• Unwilling to negotiate
• Confidant's confidence
• Like some offers
• Under wraps, so to speak