Small chess piece (4)
I believe the answer is:
pawn
'small chess piece' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pawn that I've seen before include "Chess piece -- puppet" , "Hock; cat's-paw" , "Hostage; chessman" , "Person one used" , "Chessman often sacrificed" .)