Amusingly unconventional (4)
I believe the answer is:
zany
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">amusingly unconventional</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for zany that I've seen before include "Madcap, like a clown" , "Left-field - foolish" , "Amusingly odd" , "Bizarrely comic" , "Amusingly idiosyncratic" .)