Fine clock broken by American old woman (7)
I believe the answer is:
fusspot
'old woman' is the definition.
(I've seen this before)
'fine clock broken by american' is the wordplay.
'fine' becomes 'f' (abbreviation).
'clock' becomes 'spot' (clock can mean to notice or spot).
'broken by' is an insertion indicator (inserted letters break into the word).
'american' becomes 'us' (abbreviation for United States).
'f'+'spot'='fspot'
'fspot' enclosing 'us' is 'FUSSPOT'.
(Other definitions for fusspot that I've seen before include "Old woman" , "Perfectionist" , "Pernickety person" , "one worrying about trifles" , "Person hard to please" .)