Anything reproving expresses disappointment or disapproval, like the reproving look your teacher gives you as you arrive ten minutes late for class. Again.
A reproving glance from your dog as you leave the house might make you feel a little bit guilty for not taking her for a longer walk that morning. A reproving comment on your math test will also make you feel guilty, for not studying harder. This guilt-inducing adjective comes from the verb reprove and its Latin source, reprobare, "disapprove, reject, or condemn."