A gear in a new Renault (7)
I believe the answer is:
neutral
'a gear' is the definition.
(thesaurus)
'a new renault' is the wordplay.
'a new' indicates anagramming the letters.
'renault' with letters rearranged gives 'NEUTRAL'.
'in' is the link.
(Other definitions for neutral that I've seen before include "Not favoring either side" , "Lacking a preference" , "A runlet? (anag)" , "Supporting neither side" , "Where gears are not engaged" .)