Unwelcome guest (8)
I believe the answer is:
intruder
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unwelcome guest</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 intruder that I've seen before include "Person who comes in being neither invited nor wanted" , "Housebreaker" , "Gatecrasher" , "Trespasser" , "Uninvited and unwelcome visitor" .)