really (adv.)youdaoicibaDictYouDict[really 词源字典]
c. 1400, originally in reference to the presence of Christ in the Eucharist, from real (adj.) + -ly (2). Sense of "actually" is from early 15c. Purely emphatic use dates from c. 1600; interrogative use (oh, really?) is first recorded 1815.[really etymology, really origin, 英语词源]