Cover duet off court when late (7)
I believe the answer is:
overdue
'late' is the definition.
(similar in meaning)
'cover duet off court' is the wordplay.
'off' is a deletion indicator ('off' can mean to remove).
'court' becomes 'ct' (abbreviation used in road names).
'cover'+'duet'='coverduet'
'coverduet' with 'ct' taken away is 'OVERDUE'.
'when' acts as a link.
(Other definitions for overdue that I've seen before include "Belated" , "Late for payment" , "Behindhand" , "Late like unpaid bill" , "Late, outstanding like bill" .)