nagavator
a person in the passenger's seat (usually a woman) who nags instead of navigates; a backseat driver
Jane: I think we're lost, maybe I should drive, turn here, you missed it, watch out for that squirrel, can't you drive?
Dick: Not with you carrying on like that. Geez, you're such a nagavator.
Dick: Not with you carrying on like that. Geez, you're such a nagavator.
nagavator
Passenger in an automobile who constantly tells the driver what he/she is doing wrong, where to go, how to drive, etc. Usually very wrong and very annoying.
I'm not going the wrong way! Quit being such a nagavator.