Ex-students (6)
I believe the answer is:
alumni
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">ex-students</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for alumni that I've seen before include "we studied at a certain place" , "Graduates of an institution" , "Ex-students" , "Old boys and girls" , "Put too much strain on, as Revenue Commissioners do" .)