gripe at (someone)
To complain, often continually and in an irritating manner, to someone. I turned the thermostat up, so you all can stop griping at me about how cold it is in here, thanks. Michael, as long as you have long hair, Grandma is going to gripe at you—you better get used to it.
gripe at someone
to complain to someone. Stop griping at me! There is no need to gripe at your little brother.