Be unable to contain one's rage – trudge in river (7)
I believe the answer is:
explode
'be unable to contain one's rage aeur' is the definition.
I can't tell whether this definition defines the answer.
'trudge in river' is the wordplay.
'trudge' becomes 'plod' (synonyms).
'in' is an insertion indicator.
'river' becomes 'exe' (River Exe).
'plod' placed inside 'exe' is 'EXPLODE'.
Can you help me to learn more?
(Other definitions for explode that I've seen before include "Burst outward" , "Violently shatter" , "Set off" , "Go off with a bang" , "Pop" .)