Mound of drifted sand (4)
I believe the answer is:
dune
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mound of drifted sand</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 dune that I've seen before include "Ridge of sand created by wind" , "Seashore sand hill" , "Low hill of sand, called in a desert a barkhan" , "Sandy hill" , "Nude in the sand" .)