Not evenly balanced (7)
I believe the answer is:
unequal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not evenly balanced</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for unequal that I've seen before include "Dissimilar" , "Not well matched or even" , "at different levels" , "Not in balance" , "Not fair or balanced" .)