Christopher last to write dodgy cheque (4)
I believe the answer is:
kite
'dodgy cheque' is the definition.
(term for a fraudulent cheque)
'christopher last to write' is the wordplay.
'christopher' becomes 'Kit' (short for Christopher).
'last to' indicates one should take the final letters.
The last letter of 'write' is 'e'.
'kit'+'e'='KITE'
(Other definitions for kite that I've seen before include "Soaring bird of prey" , "Small hawk" , "Child's toy; bird of prey" , "Wind-borne toy" , "aeroplane" .)