Rip-off boy in brig (6)
I believe the answer is:
prison
'brig' is the definition.
(I've seen this in another clue)
'rip-off boy' is the wordplay.
'off' indicates anagramming the letters.
'boy' becomes 'son' (male child).
'rip' is an anagram of 'pri'.
'pri'+'son'='PRISON'
'in' is the link.
(Other definitions for prison that I've seen before include "Place of confinement" , "Stir - can" , "Gaol" , "Place of detention for criminals" , "Penitentiary" .)