nod at

nod at someone

to make a motion to someone with one's head indicating a greeting, agreement, or something else. I nodded at Fred, but I really didn't agree. Molly nodded at Fred, and Fred, knowing she wanted to leave the party, went for their coats. When she offered him some ice cream, he only nodded. She thought he was rude and decided not to give him any.
See also: nod