French word fiston comes from French rejeter

Detailed word origin of fiston

Dictionary entry	Language	Definition
rejeter	French (fra)	(reflexive) to jump back, throw oneself back. To discharge, spew out. To position, place. To reject (an appeal, a lover etc.); to refute (an accusation). To throw back (a fish, etc.).
rejeton	French (fra)	(botany) shoot. (colloquial) kid. (figuratively) offshoot. (literary) scion.
fiston	French (fra)	Boy, son, lad, young man (as a form of address).

Words with the same origin as fiston