Jack the Lad 
noun British informal
A brash, cocky young man: a cocky Jack the Lad who neglected academic study [as modifier]: a Jack the Lad sex symbol...
- Good old Les, a bit of a rogue, a bit of a Jack the Lad, but basically, as Eamonn says ‘a good man’…
- I learnt to get on with them, I just wanted to be something I wasn't, a bit of a Jack the Lad and it was the start of a rocky ride really.
- Monogamy has never meant much to Jack the Lad, who admits he repeatedly lied to Anjelica during their 17-year relationship.
Origin
Nickname of Jack Sheppard, an 18th-century thief.