kickback

n (infml 口) money paid to sb who has helped one to make a profit, often illegally 回扣, 酬金（常指不合法的）.

kettledrum, key, key (also cay), key money, key signature, key-pad, key-ring, keyboard, keyhole, keynote, keystone, KG, KGB, khaki, kHz, kibbutz, kibbutznik, kick, kick-off, kick-start, kicker, kid, kid-glove, kid...into doing, kiddy (also kiddie), kidnap, kidnaper, kidnapper, kidnapping, kidney, kidney bean, kidney machine, kill, kill off, killer, killing, killjoy, kiln, kilo, kilo-,