Jeans fabric (5)
I believe the answer is:
denim
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">jeans fabric</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 denim that I've seen before include "Hard-wearing blue fabric" , "Durable material" , "Mined (anag)" , "Coloured cotton twill" , "Material for casual trousers or jackets" .)