Finished nursing little girl, cut (10)
I believe the answer is:
diminished
'cut' is the definition.
(diminish can mean to cut or reduce)
'finished nursing little girl' is the wordplay.
'finished' becomes 'did' (do can mean to complete or finish).
'nursing' is an insertion indicator.
'little' becomes 'mini'.
'girl' becomes 'she' ().
'mini'+'she'='minishe'
'did' placed around 'minishe' is 'DIMINISHED'.
(Other definitions for diminished that I've seen before include "weakened" , "run down" , "reduced" , "Not so impressive" , "Became less" .)