Bar mitzvah, for one (4)
I believe the answer is:
rite
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">bar mitzvah for one</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for rite that I've seen before include "Solemn ceremony" , "Custom" , "Formal procedure" , "Uncomplaining person" , "form of service" .)