Shell-game accessory (3)
I believe the answer is:
pea
'shell-game accessory' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pea that I've seen before include "Leguminous vegetable" , "veg" , "Tiny stone" , "Ape this plant badly" , "It grows in 23 Down" .)