Car decor (4)
I believe the answer is:
trim
'car decor' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for trim that I've seen before include "Tidy; cut" , "Lop unwanted parts off, tree or hair" , "Arrange sails to suit the weather" , "Cut away; decorate" , "Cut away protruding bits, say of hair" .)