Finally getting power to reject shoddy goods (4)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Last letters of gettinG poweR tO rejecO. Grot is a back-formation from “grotty”, which apparently was first used, or at least popularised, by George Harrison in the film A Hard Day’s Night ; it’s from a shortening of “grotesque”