Add to account about European uprising (6)
I believe the answer is:
accrue
'add to' is the definition.
'account about european uprising' is the wordplay.
'account' becomes 'ac'.
'about' becomes 'c' (abbreviation for 'circa'**).
'european' becomes 'eur' (common abbreviation).
'uprising' says the letters should be written in reverse.
'eur' written backwards gives 'rue'.
'ac'+'c'+'rue'='ACCRUE'
(Other definitions for accrue that I've seen before include "Grow by adding to" , "Grow or accumulate, say interest" , "what interest payments do" , "Build up interest" , "Show increasing interest" .)