Member drowning in river? How awful! (4,2)
I believe the answer is:
'how awful' is the definition.
(both can be expressions of dismay)
'member drowning in river?' is the wordplay.
'member' becomes 'arm' (member can mean a limb).
'drowning in' means one lot of letters goes inside another.
'river?' becomes 'dee' (River Dee).
'arm' put within 'dee' is 'DEAR ME'.
(Other definitions for dear me that I've seen before include "how distressing!" , "What a pity" , "Mild expression of distress from expensive self" , "how sad" , "Expression of mild regret from precious self" .)