Rebellious soldier with sour expression crossing gorge (3,3)
I believe the answer is:
pig out
'gorge' is the definition.
('pig out' can be a synonym of 'gorge')
'rebellious soldier with sour expression crossing' is the wordplay.
'rebellious' shows that the letters should be reversed in order.
'soldier with' becomes 'gi' (government issue or general issue. I am not sure about the 'with' bit.**).
'sour expression' becomes 'pout'.
'crossing' means one lot of letters goes inside another.
'gi' back-to-front is 'ig'.
'ig' inserted within 'pout' is 'PIG OUT'.
(Other definitions for pig out that I've seen before include "To eat a lot may" , "go on a binge" , "gorge" , "Eat too much food" , "overindulge" .)