Finished it today although some of it is repeated (5)
I believe the answer is:
ditto
'repeated' is the definition.
(I've seen this before)
'finished it today although some of' is the wordplay.
'some of' indicates the answer is hidden within the clue.
'DITTO' can be found hidden inside 'finished it today although'.
'it is' is the link.
(Other definitions for ditto that I've seen before include "In lists, the same again with two small marks" , "Copy" , "Notation meaning the same again" , "Repeat (instruction)" , "Mark used to indicate the word above it should be repeated" .)