idiotyoudaoicibaDictYouDict[idiot 词源字典]
idiot: [13] The etymological idea underlying idiot is of a ‘private individual’. That is what Greek idiótēs (a derivative of ídios ‘personal, private’) originally meant. It was extended to the ordinary ‘common man’, particularly a lay person without any specialized knowledge, and so came to be used rather patronizingly for an ‘ignorant person’. It is this derogatory sense that has come down to English via Latin idiōta and Old French idiot.
=> idiosyncracy[idiot etymology, idiot origin, 英语词源]
idiot (n.)youdaoicibaDictYouDict
early 14c., "person so mentally deficient as to be incapable of ordinary reasoning;" also in Middle English "simple man, uneducated person, layman" (late 14c.), from Old French idiote "uneducated or ignorant person" (12c.), from Latin idiota "ordinary person, layman; outsider," in Late Latin "uneducated or ignorant person," from Greek idiotes "layman, person lacking professional skill" (opposed to writer, soldier, skilled workman), literally "private person (as opposed to one taking part in public affairs)," used patronizingly for "ignorant person," from idios "one's own" (see idiom).
Reader, suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself. [Mark Twain, c. 1882]
Idiot box "television set" is from 1959; idiot light "dashboard warning signal" is attested from 1968. Idiot savant attested by 1870.