Blackthorn fruit (4)
'blackthorn fruit' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sloe that I've seen before include "Sour blackthorn fruit" , "Black fruit" , "Thorny bush with plum-like fruit" , "Fruit steeped in gin to make a liqueur" , "Fruit often used for gin" .)
'blackthorn fruit' is the definition.
(I've seen this in another clue)
This is all the clue.
(Another definition for sloes that I've seen is " Fruit of the blackthorn".)