The word "bopper" is a slang term used to describe someone who is cool, fashionable, and trendy. There are several synonyms that can be used to describe a bopper, such as hip, modish, chic, stylish, fashionable, and trendy. These words all suggest that someone is up-to-date with the latest fashions and trends and has an effortless sense of style and confidence. Other synonyms could include "bougie", "on trend", "swanky", "cool cat", or "trendsetter". No matter which synonym is used, the idea is the same - a bopper is someone who stands out for their sense of fashion and trend-setting style.