Small keepsake (5)
I believe the answer is:
token
'small keepsake' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for token that I've seen before include "Money substitute" , "Plastic coin substitute" , "Privately issued coin or voucher" , "Nominal; voucher" , "Keepsake or memorial as of friendship" .)