Translation:¡Feliz fin de semana!
Because "feliz semana" means "happy week".
Conversely, "feliz fin de semana" literally translates to "happy end of week" because there is no word for "weekend" in Spanish so we rely on a loose phrase translation rather than a word for word translation.
So i entered 'Feliz fin de' and pressed check by accident and it accepted it.. does anybody know if this is a shortened version you can use?
Buen would be "good". Feliz means happy. You could say "Yo esperanza tú tienes un buen fin de semana" as in "I hope you have a good weekend."
fin de semana = weekend
Otherwise it would have been, happy week!