error

Error, erroris is masculine, third declension, from erro, "I wander". The physical sense comes first and stays live: Virgil's errores are Aeneas going round the Mediterranean the long way, not a list of his blunders, and translating them as mistakes ruins the line. The mental sense is the same picture indoors, going astray in your thinking.

Church Latin narrows it hard. There, error is doctrinal error, heresy without the shouting, and a text that condemns the errores of a named man is condemning what he taught. English error, erratic, errant and the knight-errant who really is wandering all keep one half or the other.