Black eye, informally (6)
I believe the answer is:
shiner
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">black eye informally</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 shiner that I've seen before include "Mouse" , "Possible end of scrapping" , "device that lightens one's work" , "Black eye - small glittering fish" , "Informal black eye - see how it glows" .)