freedom rider
noun
- US a person who challenged racial laws in the American South during in the 1960s, originally by refusing to abide by the laws governing the segregation of seating in buses〈美〉自由乘车运动参加者（20世纪60年代挑战美国南方种族歧视法律的人, 最初的做法是拒绝服从规定乘坐公交车时实行种族隔离的法律）。