Arrival, coming (6)
I believe the answer is:
advent
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">arrival</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(advent is a kind of arrival)</span><br/ ><br/ >'<span class="explanation-format__original">coming</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(advent is the arrival or coming of something)</span><br/ ><br/ ></span>
(Other definitions for advent that I've seen before include "Period in the Christian calendar" , "Second Coming" , "introduction" , "Period before Christmas" , "Coming - occasion in Church calendar" .)