Convertible frequently held by red light (4,3)
I believe the answer is:
soft top
'convertible' is the definition.
(I've seen this in another clue)
'frequently held by red light' is the wordplay.
'frequently' becomes 'oft' (oft can mean frequently, eg oft-quoted).
'held by' indicates putting letters inside.
'red light' becomes 'stop' (I've seen this in another clue).
'oft' inserted into 'stop' is 'SOFT-TOP'.
(Other definitions for soft top that I've seen before include "Fancy car" , "Type of convertible car" , "Car with a folding roof" , "Vehicle" , "Alternative to saloon" .)