How can I say the opposite of "appetite go"? Like, when I don't want to eat anything, what should I put after "appetite"?
The opposite of "get an appetite going" is to "lose an appetite", with the verb "lose" placed before "appetite". To "lose one's appetite" means that someone no longer has an appetite or is no longer hungry. This means that someone once had an appetite, but something caused it to go away. If you just want to say that someone is not hungry, you can say that they "don't have an appetite". Ex: I was hungry but after hearing the bad news, I've lost my appetite. Ex: He hasn't had an appetite for a few days.