### Clue: Unrepentant singer (4)
### Answer: PIAF 
 ### Explanation: Definition: Unrepentant singer
 Cryptic defn: Reference to a songstress, one of whose famous numbers was the French "Non, je ne regrette rien", translated as "No, I do not regret anything" ie. I'm unrepentant. English versions were entitled "No Regrets".  Nice!