Tussock (5)
I believe the answer is:
clump
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tussock</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for clump that I've seen before include "Compacted mass" , "Bunch" , "A compact mass" , "Rough cluster or heavy tramping sound" , "Clod, lump" .)