### Clue: Give thickhead the boot, ultimately with a show of remorse? (9)
### Answer: SACKCLOTH 
 ### Explanation: Definition: a show of remorse
 SACK (dismiss …;give … the boot) CLOT(a thickhead;an idiot) + **last letter of**(ultimately) "with".
Defn: Coarse fabric worn to demonstrate one's remorse or repentance.