Is it ensure, insure, or assure?
"handled hitting device used in tennis, etc.," c.1500, probably originally "tennis-like game played with open hand" (late 14c.), from Middle French rachette, requette (Modern French raquette) "racket for hitting; palm of the hand," perhaps via Italian racchetta or Spanish raqueta, both from Arabic rahat, a form of raha "palm of the hand." Cf. French jeu de paume "tennis," literally "play with the palm of the hand" (cf. tennis).