forget (one's) manners

forget (one's) manners

To act in a rude, impolite, or otherwise inappropriate way. I'm sorry, I didn't mean to reach across the table like that—I must have forgotten my manners for a minute there. How could you say something like that to me? Have you forgotten your manners?
See also: forget, manner

forget one's manners

to do something ill-mannered. Jimmy! Have we forgotten our manners?
See also: forget, manner