Small area surrounded by water (5)
I believe the answer is:
islet
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">small area surrounded by water</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 islet that I've seen before include "Little bit of land" , "Stile (anag)" , "Tiles (anag.)" , "Small landmass" , "Detached territory" .)