Gamble full of Northern flair (4)
I believe the answer is:
bent
'flair' is the definition.
(I've seen this in another clue)
'gamble full of northern' is the wordplay.
'gamble' becomes 'bet' (bet is a kind of gamble).
'full of' means one lot of letters goes inside another.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'bet' enclosing 'n' is 'BENT'.
(Other definitions for bent that I've seen before include "Distorted" , "Special skill" , "Natural aptitude" , "Propensity, preference" , "Warped" .)