The phrase "most ill bred" refers to someone who is lacking in manners, etiquette, or social graces. An antonym for this phrase would be "most well-bred," which means someone who is cultured, refined, and possesses excellent manners. Another antonym for "most ill-bred" would be "most polished," which indicates a person who is attentive to social norms, has good taste in clothing and decor, and is well-mannered. In contrast, "most boorish" is another antonym for "most ill-bred" and refers to someone who is crude and insensitive in their behavior towards others. Ultimately, having good breeding and manners is a positive trait that elevates individuals in social and professional settings.