An obsessive fan is someone who is extremely passionate and devoted to a particular person, group, or activity. This term can be broken down into three words: Stan (4 letters), NERD (4 letters), and NUT (3 letters). A Stan is an enthusiastic and devoted fan, a NERD is someone who is highly knowledgeable about a certain topic, and a NUT is someone who is obsessed with something. Together, these three words form the term 'Obsessive Fan, ' which describes someone who is extremely passionate and devoted to a particular person, group, or activity.