Totally unfamiliar (5)
I believe the answer is:
alien
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">totally unfamiliar</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 "Little green man, perhaps" , "Clanger?" , "Stranger" , "Foreign, strange" , "Otherworldly" .)