Possible Clues:

• Become fixed
• Harden hearts of those lasses, pacifist pussycats
• Become rigid and inflexible
• Loss, if York houses become fixed
• Turn into fossil? Most of fossil badly done, ending in ignominy
• Cause to become stiff and/or bony
• Petrify East German finally at the borders
• Harden, if held captive by authoritarian, blowing top
• Become inflexible whenever shaven-headed authoritarian is around
• To become inflexible in habits or attitudes