Canis lupis robertus
[Ringo steps up to Doc]
Ringo: You must be Doc Holliday.
Doc: [Careless, drunk, and not looking very well] That's the rumor.
Ringo: You retired too?
Doc: Not me. I'm in my prime.
Ringo: [Dubious and insulting] Yeah, you look it.
Doc: And you must be Ringo. Look, darlin', Johnny Ringo. The deadliest pistoleer since Wild Bill, they say. What do you think, darlin'? Should I hate him?
Kate: You don't even know him.
Doc: Yes, but there's just something about him. Something around the eyes, I don't know, reminds me of... me. No. I'm sure of it, I hate him.
Wyatt: [To Curly Bill and Johnny, holding up hands in placatory gesture.] He's drunk.
Now the good stuff!
DOC: In vino veritas.
JOHNNY: Age quod agis.
DOC: Credat Judaeus Apella, non ego.
JOHNNY: Iuventus stultorum magister.
DOC: In pace requiescat.
In vino veritas.
"In wine there is truth." A common enough Latin aphorism, meaning that alcohol consumption is like a truth serum. Doc is therefore overruling what his 'darlin'' has said; indeed, he hates Johnny.
Age quod agis.
The next line literally means, "Do what you do," but is better translated, "Pay attention to what you do" [i.e., you had better watch yourself]. Thus, Johnny responds that Doc ought to watch what he is saying.
Credat Judaeus Apella, non ego.
"Let Apella the Jew believe, not I." Horace's Satires, book 1, satire 5, lines 100-101. Doc's response is to quote the ancient satirist, who in this case is making fun of Jews who believe that there is divine power behind the gurgling action of a fountain. Horace, the "secular" Roman is suggesting the Jew is a fool to believe something like this is of divine origin. Thus, Doc's use of the line would suggest that Johnny Ringo is a fool to think that he can warn Doc to watch out for himself.
Iuventus stultorum magister.
"Youth is the teacher of fools." Johnny tries to be equally insulting by saying that Doc's youthful inexperience makes him foolish.
In pace requiescat.
"May he rest in peace." Doc's final words, a common enough phrase in Latin of all ages, suggests that Doc is just about ready to put an end to this conversation by finishing off Johnny. But a deadly result is averted for now.
Latin Dialogue in Tombstone