supporter

noun

1. a person who backs a politician or a team etc."all their supporters came out for the game"
2. someone who supports or champions something
3. a person who contributes to the fulfillment of a need or furtherance of an effort or purpose"my invaluable assistant"
4. a band (usually elastic) worn around the leg to hold up a stocking (or around the arm to hold up a sleeve)
5. a support for the genitals worn by men engaging in strenuous exercise