eruditeyoudaoicibaDictYouDict[erudite 词源字典]
erudite: [15] To be erudite is literally to be the opposite of ‘rude’. Latin rudis (source of English rude) meant ‘rough, unpolished’, and so ērudīre, a compound verb formed with the prefix ex- ‘out of, from’, signified ‘take the roughness out of’, hence ‘polish, teach’. Its past participle formed the basis of an adjective, ērudītus ‘(well) taught’, which as borrowed into English has acquired the greater gravitas of ‘learned’.
=> rude[erudite etymology, erudite origin, 英语词源]
erudite (adj.)youdaoicibaDictYouDict
early 15c., "learned, well-instructed," from Latin eruditus "learned, accomplished, well-informed," past participle of erudire "to educate, teach, instruct, polish," literally "to bring out of the rough," from assimilated form of ex- "out" (see ex-) + rudis "unskilled, rough, unlearned" (see rude). Related: Eruditely.