Senior copper bags stolen garment (5)
I believe the answer is:
dhoti
'garment' is the definition.
(dhoti is a kind of garment)
'senior copper bags stolen' is the wordplay.
'senior copper' becomes 'di' (detective inspector, type of copper. I am not sure about the 'senior' bit.).
'bags' means one lot of letters goes inside another (bag can mean secures or steals).
'stolen' becomes 'hot' (stolen goods are 'hot').
'di' going around 'hot' is 'DHOTI'.
Can you help me to learn more?
(Other definitions for dhoti that I've seen before include "article of clothing" , "Loin cloth" , "Hindu loincloth" , "Cloth round middle" , "Indian loincloth" .)