Gravel (4)
I believe the answer is:
grit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">gravel</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 grit that I've seen before include "Determination - small stones" , "Small loose particles of stone" , "Grains of rock or sand" , "Small particles of sand etc" , "Gravelly courage" .)