It's a French corruption — fitchet — of the Dutch wordvissewhich means — "nasty.".    From Wordnik.com.  [A Night of Furversion] Reference

Geronimo's a few weeks before when he rushed up to him to show his hunting spoils, a fitchet and several birds which he had killed with his pretty little cross-bow, a gift from Dona Magdalena.    From Wordnik.com.  [Complete Project Gutenberg Georg Ebers Works] Reference