Tennis Foul Caused by Overstepping the Baseline
Puzzle 1 of Hand Sports Medium Pack
Question is: Tennis Foul Caused by Overstepping the Baseline
and the answer is: FOOTFAULT
Word Meaning:
FOOT FAULT — (sports) In certain sports, as in tennis or long jump, a fault in which the athlete's foot is in the wrong place at the wrong time.
Definitions from Wiktionary.