1. a person who participates in motocross racing
Usage: common in sports contexts
2. a motorcycle designed and used for motocross racing
Usage: less common than sense 1; sometimes used informally

Examples

• The young motocrosser trained every weekend to prepare for the championship.
• Professional motocrossers compete on challenging off-road tracks.
• He became a motocrosser after years of riding dirt bikes recreationally.
• The motocrosser navigated the muddy course with impressive skill.
• Many motocrossers start their careers in youth racing leagues.
• She dreamed of becoming a professional motocrosser since childhood.