Conduct oneself properly (6)
I believe the answer is:
behave
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">conduct oneself properly</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 behave that I've seen before include "Handle" , "Conduct oneself properly" , "Act or react - show good manners" , "Act in a certain manner" , "Act correctly" .)