Springbok (8)
I believe the answer is:
antelope
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">springbok</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for antelope that I've seen before include "One leapt badly on the graceful animal" , "Springbok or gnu?" , "Reebok perhaps" , "it runs very quickly" , "fast buck, perhaps?" .)