Yawn (4)
I believe the answer is:
gape
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">yawn</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that yawn can be written as gape)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for gape that I've seen before include "Yawn" , "Look with mouth wide open" , "wide opening" , "Hang wide open" , "Stare with open mouth in wonder" .)