Additional craft recalled by one-time partner (5)
I believe the answer is:
extra
'additional' is the definition.
(I've seen this before)
'craft recalled by one-time partner' is the wordplay.
'craft' becomes 'art' (both can mean cunning or trickery).
'recalled' shows that the letters should be reversed in order.
'by' means one lot of letters go next to another.
'one-time partner' becomes 'ex'.
'art' written backwards gives 'tra'.
'tra' put after 'ex' is 'EXTRA'.
(Other definitions for extra that I've seen before include "One playing small part" , "Possibly a bad ball" , "One playing a minor part" , "walk-on part" , "to boot" .)