Wear away, as soil (5)
I believe the answer is:
erode
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wear away as soil</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for erode that I've seen before include "go to pieces!" , "Gradually wear away" , "'Deteriorate, wear away (5)'" , "Abrade" , "Become ground down or deteriorate" .)