Ankle-length skirt (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">ankle-length skirt</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 maxi that I've seen before include "Long length skirt" , "full length garment" , "Full-length skirt" , "Long dress" , "racing yacht" .)