Thick woollen cloth (5)
I believe the answer is:
tweed
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">thick woollen cloth</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 tweed that I've seen before include "Woollen cloth - Scotland/England border river" , "Thick woolen fabric" , "flows across a border" , "Harris cloth" , "rough stuff" .)