1 : someone who endorses a motion or petition as a necessary preliminary to a discussion or vote
2 : a follower who is not a member of an ingroup
3 : someone who expounds and interprets or explains
4 : a supporter who accepts something as true
5 : a person who accepts the leadership of another
6 : an ardent and enthusiastic supporter of some person or activity
7 : someone who supports or champions something
8 : an enthusiastic devotee of sports