Denim trousers (5)
I believe the answer is:
jeans
'denim trousers' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for jeans that I've seen before include "(Usually) blue casual wear" , "Strides casually" , "Denim trousers" , "Casual trousers, sometimes stonewashed?" , "article of clothing" .)