Engage in digging up river to confine smell (6)
I believe the answer is:
exhume
'engage in digging up' is the definition.
I can't judge whether this definition defines the answer.
'river to confine smell' is the wordplay.
'river' becomes 'exe' (River Exe).
'to confine' indicates putting letters inside.
'smell' becomes 'hum' (I have seen 'Unpleasant smell ' mean 'hum' so perhaps 'smell' could also mean 'hum').
'exe' enclosing 'hum' is 'EXHUME'.
Can you help me to learn more?
(Other definitions for exhume that I've seen before include "Reveal" , "Dig up (a corpse)" , "Disinter a dead body" , "Dig up, unearth" , "opposite of 5 [ENTOMB]" .)