Agile athlete (7)
I believe the answer is:
gymnast
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">agile athlete</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 gymnast that I've seen before include "One skilled in athletic exercises" , "he may be in for the high jump" , "Exercise" , "One skilled in physical exercises" , "My angst over indoors athlete" .)