There are numerous synonyms for the phrase "be unpopular," and each word has its own unique definition and connotation. One synonym is "be disliked," which indicates that someone or something is not well-liked or accepted. Another synonym is "be unloved," which implies a lack of affection or support. "Be reviled" means to be hated or condemned, while "be scorned" suggests a strong disdain or contempt towards someone or something. "Be shunned" also signifies rejection or exclusion from a social group or community. Lastly, "be ostracized" refers to the act of casting someone out or excluding them from a society or group.