Completely foreign (5)
I believe the answer is:
alien
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">completely foreign</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 alien that I've seen before include "ET" , "Foreign; extraterrestrial" , "Creature from another planet" , "extraneous" , "Offensive" .)