Material used to make jeans (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
denim
(Other definitions for denim that I've seen before include "dark blue material" , "Coloured cotton twill" , "Hard-wearing clothing material, twilled cotton" , "Mined badly for a hard-wearing fabric" , "Twilled cotton fabric" .)