Most strange (6)
I believe the answer is:
oddest
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">most strange</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for oddest that I've seen before include "most bizarre" , "Strangest" , "Most unusual or uneven" , "Queerest" , "Most rum" .)