fiesta

party; feast; feast day (of a saint); holiday

“Y buscábanle los Judíos en la fiesta, y decían: ¿Dónde está aquél?” — And the Jews were looking for him at the feast, and saying: Where is he?

Inherited from Old Spanish fiesta, from Late Latin fĕsta, from Latin fēsta, plural of fēstum. It is unclear why the initial f- stayed in this word instead of becoming the expected h-, perhaps from a learned coloring.