Ox; guide (5)
I believe the answer is:
steer
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">ox</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(castrated ox)</span><br/ ><br/ >'<span class="explanation-format__original">guide</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that guide can be written as steer)</span><br/ ><br/ ></span>
(Other definitions for steer that I've seen before include "Guide (eg, a ship)" , "The animal to direct" , "Exercise control" , "Navigate" , "Control movement" .)