Too much on the other side? (4)
I believe the answer is:
over
I believe this clue is a double definition.
'too much' is the first definition.
(over can mean to too great an extent)
'on the other side?' is the second definition.
(I've seen this in another clue)
(Other definitions for over that I've seen before include "The delivery is concluded" , "completed" , "Finished - across - in excess" , "left for another day?" , "Excessive" .)