Non-attendance (7)
I believe the answer is:
absence
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">non-attendance</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 absence that I've seen before include "Cause of fonder heart?" , "Non-presence" , "Need" , "form of inattention?" , "''. . . . . . . makes the heart grow fonder'' (7)" .)