Part from grille a vent covers (5)
I believe the answer is:
leave
'part' is the definition.
(thesaurus)
'from grille a vent covers' is the wordplay.
'from' says the answer is hidden in the clue.
'LEAVE' is hidden in the letters of 'grille a vent covers'.
(Other definitions for leave that I've seen before include "Brexit's aim" , "Permission - time off" , "Something taken by those withdrawing" , "Relinquish - holiday" , "Depart, go" .)