Coarse cloth (6)
'coarse cloth' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tweed that I've seen before include "Sort of jacket" , "River on border between England and Scotland" , "Harris cloth" , "Rough material" , "River; rough cloth" .)
(Other definitions for denim that I've seen before include "Twill cloth" , "Hard-wearing cotton fabric" , "Coloured cotton twill" , "Thick cotton cloth" , "Hard-wearing material seen in jeans" .)
(Other definitions for canvas that I've seen before include "Tent material" , "Heavy cloth of sails, tents etc" , "Artist's cloth" , "Strong coarse cloth" , "Cloth for painting etc" .)