Broken line that’s overlooked in commotion (6)
I believe the answer is:
bustle
'commotion' is the definition.
(I know that bustle is a type of commotion)
'broken line that's overlooked in' is the wordplay.
'broken' becomes 'bust' (bust can mean broken).
'that's overlooked' suggests deleting specific letters.
'line' with 'in' taken away is 'le'.
'bust'+'le'='BUSTLE'
(Other definitions for bustle that I've seen before include "Excited activity - or padding at rear of old skirt" , "Padding once used to pad out back of skirt" , "Scurry - frame worn under skirt" , "Hurly-burly" , "A subtle sort of commotion" .)