"Variant of Llewellyn"
The name Llewyn is commonly a male name from the "Welsh" origin.
Llewyn is a spelling of Llewellyn, an anglicised form of the Welsh name Llywelyn, borne by the medieval Welsh princes Llywelyn the Great and Llywelyn the Last. The first element is Welsh llyw, meaning leader or ruler. The same spelling is used for the title character of the 2013 film Inside Llewyn Davis.
Llewellyn means "Lion-like friend, Lightning.".
The pronunciation of Llewyn is LOO-in.