Dishonor on you! Dishonor on your cow!
Fi al vi! Fi al via bovino!
I waited for someone to say that...
What kind of word is "fi" grammatically? "Shame" seems to be an abstract noun, but there is no "-o" ending here for the esperanto version.
It's an interjection (so, a kind of exclamation word).
Those are often a bit outside the usual grammatical rules; for example, you might have "nuh-uh" or "pfff" in English, with sounds that are not usually found in "normal" content words.
In addition, there's another word for shame, honto.
Fi is an interjection expressing disapproval or disgust.
It is still also used in Norwegian and Swedish and is "fy", it was earlier also used in English: https://en.wiktionary.org/wiki/fy#English
I just tried it. They accept "Fie on you!"
I love the Esperanto guys.
And German "Pfui!", which I had always assumed was the source.
One also sees "fie!" in (older) English, e.g. "fie, for shame!"
Ekzistas malnova proverbo en Tenesio - mi scias ke estas en Teksaso, versxajne en Tenesio - kiu diras, trompi min unufoje, honto sur - honto sur vi. Trompi min - oni ne povas trompigxi denove. - eksprezidento Bush
The English translation is given as "Shame on you!", which is more common than "Shame to you!" So could you say is "Fi sur vi!" or is that to literal of an on?
I think "sur" is unnecessarily specific but I would accept "fi sur vin" (accusative of direction, which "al" does not need).