Coppers in prison cell, half cut (5)
I believe the answer is:
pence
'coppers' is the definition.
(copper can mean a penny coin)
'prison cell half cut' is the wordplay.
'prison' becomes 'pen' (both can mean an enclosure).
'half cut' indicates taking half.
'cell' cut in half is 'ce'.
'pen'+'ce'='PENCE'
'in' is the link.
(Other definitions for pence that I've seen before include "British coins" , "Small quantity of money" , "Copper coins" , "some European capital" , "''... fumble in a greasy till/and add the halfpence to the ...'' (Yeats)" .)