Fruit of the blackthorn (4)
I believe the answer is:
sloe
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fruit of the blackthorn</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sloe that I've seen before include "Blackthorn, used in making a type of gin" , "Fruit of the blackthorn does't sound fast" , "Sour blackthorn fruit" , "Musical study" , "Black fruit" .)