Topped out (6)
I believe the answer is:
peaked
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">topped out</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 peaked that I've seen before include "Reached the height of one's powers" , "Reached highest point, say of fitness" , "Reached one's greatest capacity" , "levelled out" , "Reached maximum intensity" .)