noun
sparring partner
Borrowed from English; used in boxing and martial arts for a training partner who practices with a fighter. Also used figuratively for a practice opponent in debates or negotiations.
彼は試合前にスパーリングパートナーと練習した。
He practiced with his sparring partner before the match.
討論の練習で、友達がスパーリングパートナー
My friend acted as a sparring partner for debate practice.