credo quia absurdum [ˈkreɪ:dəʊ 'kwiə æbˈsɜːdəm] int. also credo quia absurdum est
1.) 'I believe because it is absurd' (Dictionary of Foreign Words, Adrian Room, 2000).
Etymology: Latin, from credo, 1st person singular present indicative of credere, to believe + quia, because + absurdum, absurd. The phrase is a misquotation from Tertullian's On The Flesh of Christ, ~206. The actual quote is "Crucifixus est dei filius; non pudet, quia pudendum est. Et mortuus est dei filius; credibile prorsus est, quia ineptum est. Et sepultus resurrexit; certum est, quia impossibile." (The Son of God was crucified; I am not ashamed, because it is shameful. The Son of God died; it is immediately credible, because it is silly. He was buried, and rose again; it is certain, because it is impossible.")
"Many have no doubt attained to that humility which says: credo quia absurdum est and sacrificed their reason to it: but, so far as I know, no one has yet attained to that humility which says credo quia absurdus sum, though it is only one step further" (Daybreak by Friedrich Nietzsche, R. J. Hollingdale (trans.), 1982).
(Die Jungfrau züchtigt das Jesuskind vor drei Zeugen: André Breton, Paul Éluard und dem Maler, Max Ernst, 1926)
Bonus nerd points for the first person to translate the 2nd Latin phrase in the quote!