Pursuer (6)
I believe the answer is:
chaser
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">pursuer</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that pursuer can be written as chaser)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for chaser that I've seen before include "Hunter; drink" , "one in the national hunt" , "Racing horse" , "A drink like beer after whisky" , "Drink that follows immediately after another one" .)