Come about (5)
(Other definitions for occur that I've seen before include "Spring to mind" , "Happen, transpire" , "Go on" , "Befall" , "Turn up" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">come about</span>' is the definition.<br/ ><span class="explanation-format__explanation">(arising is a kind of coming about)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for arise that I've seen before include "Get or stand up" , "Originate; get up" , "Spring - get up" , "Wake up or get up" , "Ascend" .)