Young male horses (5)
I believe the answer is:
colts
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">young male horses</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 colts that I've seen before include "Young male horses" , "young players" , "Young stallions" .)