Doorpost (4)
I believe the answer is:
jamb
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">doorpost</span>' is the definition.<br/ ><span class="explanation-format__explanation">(post holding up a door)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for jamb that I've seen before include "bit on the side?" , "part of doorway?" , "Vertical part to a doorframe" , "Side of door frame" , "Door, window side post" .)