Backer (noun)

1. A person who provides financial or other support to a project, person, or cause.
2. A person who supports or advocates for something or someone.
3. A person who invests money in a venture in exchange for a share of the profits.

Origin:

Derived from the verb 'back' meaning to support.

Examples:

1. He was the main backer of the new startup company.
2. She was a steadfast backer of environmental causes.
3. The billionaire was a well-known backer of political candidates.
4. The athlete had many backers who supported his career.
5. The film received backing from several major movie studios.