Fashion range used casual garment (9)
I believe the answer is:
dungarees
'casual garment' is the definition.
(type of casual clothing)
'fashion range used' is the wordplay.
'fashion' is an anagram indicator.
'range'+'used'='rangeused'
'rangeused' anagrammed gives 'DUNGAREES'.
(Other definitions for dungarees that I've seen before include "Overall" , "overalls required" , "protection at work" , "Work overalls" , "Overalls of cotton fabric" .)