Rob’s winter garment (6)
I believe the answer is:
fleece
This could be a double definition.
'rob's' is the first definition.
(synonyms)
'winter garment' is the second definition.
'fleece' can be an answer for 'garment' (I've seen this before). I am not sure about the 'winter' bit.
Can you help me to learn more?
(Other definitions for fleece that I've seen before include "Charge too much" , "coat is needed" , "Swindle; sheep's coat" , "9ac's coat" , "Do some asset stripping" .)