Alter course (4)
I believe the answer is:
veer
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">alter course</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 veer that I've seen before include "Suddenly change direction" , "Deviate" , "Change direction sharply" , "Change direction or course, like wind" , "Swing around" .)