#1: a type of brown noser who nods in response to every statement by a person of authority or higher social status
#2: a person who nods mindlessly during a conversation he or she doesn't care about or understand
#1: "Bobby is so annoying. Not only did he keep telling Ms. Smith how amazing her ideas were, that bobble-head nodded so often it looked he lacked the ability to keep his head still."
#2: "Kayla is such a bobble-head. Even though she is nodding while talking with James, her confused face proves she has no idea what he is talking about."