officeholder
A person chosen to serve in an official government position.
An officeholder is someone who has been elected or appointed to an official position of responsibility or authority. When your class elects a president for student council, that student becomes an officeholder. Mayors, governors, senators, and the President are all officeholders because they hold offices in government.
The word combines office (a position of authority or responsibility) with holder (someone who possesses something). Think of it like holding a title in a video game or sport, except these positions come with real duties and powers. A county sheriff is an officeholder with the responsibility of enforcing laws. A school board member is an officeholder who helps make decisions about education in their community.
Officeholders usually serve for a specific term: maybe one year for student council, four years for a mayor, or six years for a senator. During their time in office, they're expected to fulfill the duties of their position and serve the people who elected or appointed them. When their term ends, they either run for reelection or pass the office to someone new. The peaceful transfer of power from one officeholder to the next is one of the foundations of a democratic government.