The antonyms for "un gentlemanly" are words that indicate qualities that are commonly associated with gentlemen. Some antonyms include courteous, chivalrous, polite, well-mannered, gracious, refined, cultured, and civil. These words all suggest a person who is respectful and considerate of others, and who conducts themselves with dignity and good manners. Being gentlemanly is often associated with traits such as kindness, honesty, and integrity, as well as a commitment to doing what is right and fair. In contrast, "un gentlemanly" behavior is characterized by rudeness, disrespect, and a lack of consideration for others, which is why the antonyms are so important in demonstrating positive behaviors and attitudes.