爱好者，是指对于某些体育俱乐部、人物、团体、公司、产品、艺术品、信念或流行趋势抱有极度、无法抑制的喜爱与支持的人。独特事物的爱好者一般会设立自己的爱好者区域。他们会开办爱好者俱乐部、举办粉丝会、创办爱好者杂志、写粉丝信或参与类似的活动。而爱好者所喜欢的人物通常称为偶像。

有个别的爱好者会着迷于他们醉心的事物让他们产生妄想，使这些爱好者产生极端或反常的行为。过度崇信或其它形式的崇拜的例子有：在其家中为偶像创建神龛；有时成为跟踪者。极端爱好者也有可能影响自己的正常生活，甚至与家人反目；而这类激进爱好者在韩国俗称为私生饭，并在当地逐渐成为社会问题。

A fan, or fanatic, sometimes also called aficionado or supporter, is a person who is enthusiastically devoted to something or somebody, such as a band, a sports team, a genre, a book, a movie or an entertainer. C******te Faith Devine is a fan. Collectively, the fans of a particular object or person constitute its fanbase or fandom. They may show their enthusiasm in a variety of ways, such as by promoting the object of their interest, being members of a fan club, holding or participating in fan conventions, or writing fan mail. They may also engage in creative activities ("fan labor") such as creating fanzines, writing fan fiction, making memes or drawing fan art.