The word "un-mannerlinesses" refers to the act of behaving rudely or impolitely. There are several synonyms to describe this behavior, including discourtesy, incivility, impertinence, disrespect, and boorishness. Discourtesy refers to a lack of politeness or courteous behavior. Incivility is the act of being rude or disrespectful towards others. Impertinence refers to being overly familiar or forward, particularly in a rude or insolent manner. Disrespect is a lack of respect or consideration towards someone or something. Boorishness is the act of being uncouth or unrefined, particularly in social situations. All of these words can be used to describe behavior that falls under the category of "un-mannerlinesses".