Fallen idol is a term used to describe someone who has disappointed their followers or admirers due to bad behavior. There are several synonyms for this term that are commonly used, including has-been, disgraced, fallen star, ex-hero, and fallen angel. A has-been is someone who was once famous or successful but is no longer relevant. A disgraced person has lost honor or suffered public shame. A fallen star is someone who was once highly regarded but has lost their luster. An ex-hero is someone who was once a hero but has since lost their status. Lastly, a fallen angel is someone who was once good, but has since become evil.