Overalls fabric (5)
I believe the answer is:
denim
'overalls fabric' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for denim that I've seen before include "Twill cloth" , "Hard-wearing blue fabric" , "Hard-wearing clothing material, twilled cotton" , "Twilled cotton fabric" , "Mined badly for a hard-wearing fabric" .)