Jekyll
Jekyll (name) means a surname, famous as the name of Dr. Henry Jekyll in Robert Louis Stevenson's novella "The Strange Case of Dr Jekyll and Mr Hyde.". Example: “His sudden mood swings earned him the nickname "Jekyll and Hyde.”
Fill the gap
Can you complete this real example?
His sudden mood swings earned him the nickname "_____ and Hyde."
Etymology
This name comes from a Breton name that also appears in various forms in French, such as Judicaël, Gicquel and Jézéquel, and ultimately goes back to Old Breton Iudicael, the name of a Breton king venerated as a Catholic saint. His name was made up of Old Breton iudd (“lord, ruler, prince”) and Old Breton cael (“generous, noble”), from which modern Breton cael (“generous, noble”) also derives.