Wear a long face (4)
I believe the answer is:
mope
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wear a long face</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for mope that I've seen before include "Move around slowly and aimlessly" , "Feel dejected and apathetic" , "Move listlessly and aimlessly" , "Be listless over poem" , "Pine - sulk" .)