footfault
/ˈfʊtˌfɔlt/
noun
- In tennis and similar sports, an illegal serve in which the server's foot touches or crosses the baseline before hitting the ball.
- Practicing your serve helps avoid a footfault during a match.
- The umpire called a footfault because the player's toe touched the line.
- She lost the point after a footfault on her second serve.