Season of Pentecost (7)
I believe the answer is:
whitsun
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">season of pentecost</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for whitsun that I've seen before include "Pentecost season" , "holiday?" , "Holy Spirit festival" , "Spring festival" , "Feast" .)