Rare or unusual item (5)
I believe the answer is:
curio
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rare or unusual item</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 curio that I've seen before include "Intriguing object worth collecting" , "something odd" , "Rare thing sought for collection" , "Interesting object of rarity or difference" , "Antique" .)