In a material sense, I'm at a loose end (5)
I believe the answer is:
denim
'in a material sense' is the definition.
I can't tell whether this definition defines the answer.
'i'm at a loose end' is the wordplay.
'at' means one lot of letters go next to another (I've seen this in other clues).
'a loose' indicates an anagram (letters are loosened from their original positions).
'end' with letters rearranged gives 'den'.
'im' put after 'den' is 'DENIM'.
Can you help me to learn more?
(Other definitions for denim that I've seen before include "Durable material" , "Material for casual trousers or jackets" , "Hard-wearing clothing material, twilled cotton" , "Cotton twill fabric" , "Coarse durable twill-weave cotton fabric" .)