Unmannerly means behaving rudely or without good manners. An unmannerly guest might interrupt conversations, grab food without waiting their turn, or forget to say thank you. Someone acting in an unmannerly way ignores the basic courtesies that make group life pleasant.

When a student talks back to a teacher or pushes through a doorway without holding it for the person behind them, that's unmannerly behavior.

Unmannerly is slightly old-fashioned sounding, but it captures something specific: a consistent pattern of ignoring the considerate behaviors that show respect for others. You might forget to say please once because you're distracted, but someone who regularly ignores polite behavior is being unmannerly.