Jack the Lad British noun informal slang
He's a bit of a Jack the Lad - he flirts with lots of girls and doesn't care about what others think.
Peter used to be a bit of a Jack the Lad - that is why I was very surprised when he settled down and got married.
To not wonder, worry or be surprised about what is not predicted will happen in life because anything could happen
This slang derived from the 1800s. It is not sure if it comes from a real person named Jack, but there are some sources saying that it comes from Jack Shepherd - a thief from the 1700s who was said to be confident, wild and exciting.