fan
不安

n : lit. "anxiety" - A slang way to say fan (ファン)

fukkatsu
復活

v : lit. "revival" - When a band comes back from an activity or a disbandment, either to continue activity as a band, or just to special one-time only lives

furi
振り

n : The hand movements and sometimes dances that are done for certain songs. Some bands have specialized furi, but there is also generic furi that anyone can do. Please see the SPECIAL link above for a more in-depth explanation
also written:: 振り付け(furitsuke)

furukabu
古株

n : lit. "old-timer" - A fan who has been around since a band's beginning