Mirror image (4)

I believe the answer is:
self
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mirror image</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for self that I've seen before include "Will the writer?" , "One's individuality" , "Personality" , "one's identity" , "Person's distinct identity" .)