Summed up (5)
I believe the answer is:
added
This clue might be a double definition.
'summed' is the first definition.
('add' can be a synonym of 'sum')
'up' is the second definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for added that I've seen before include "Contributed" , "Counted up" , "Extra" , "Totted" , "Said" .)