supporter

(noun) a person who backs a politician or a team etc.. Synonyms: protagonist, champion, admirer, booster, friend. Examples: "All their supporters came out for the game." "They are friends of the library."

(noun) someone who supports or champions something. Synonyms: patron, sponsor.

(noun) a person who contributes to the fulfillment of a need or furtherance of an effort or purpose. Synonyms: assistant, helper, help. Examples: "My invaluable assistant." "They hired additional help to finish the work."

(noun) a band (usually elastic) worn around the leg to hold up a stocking (or around the arm to hold up a sleeve). Synonyms: garter.

(noun) a support for the genitals worn by men engaging in strenuous exercise. Synonyms: athletic supporter, suspensor, jockstrap, jock.