quack: English has two words quack. The one denoting the call of a duck [17] originated of course as an imitation of the sound itself. Quack ‘person claiming to be a doctor’ [17] is short for an earlier quacksalver, which etymologically denoted ‘someone who prattles on or boasts about the efficacy of his remedies’. It was borrowed from early modern Dutch quacksalver, a compound formed from the now obsolete quacken ‘chatter, prattle’ and salf, the Dutch relative of English salve.
quack (v.)
"to make a duck sound," 1610s, earlier quake (1520s), variant of quelke (early 14c.), of echoic origin (compare Middle Dutch quacken, Old Church Slavonic kvakati, Latin coaxare "to croak," Greek koax "the croaking of frogs," Hittite akuwakuwash "frog"). Middle English on the quakke (14c.) meant "hoarse, croaking." Related: Quacked; quacking.
quack (n.1)
"medical charlatan," 1630s, short for quacksalver (1570s), from obsolete Dutch quacksalver (modern kwakzalver), literally "hawker of salve," from Middle Dutch quacken "to brag, boast," literally "to croak" (see quack (v.)) + salf "salve," salven "to rub with ointment" (see salve (v.)). As an adjective from 1650s. The oldest attested form of the word in this sense in English is as a verb, "to play the quack" (1620s). The Dutch word also is the source of German Quacksalber, Danish kvaksalver, Swedish kvacksalvare.
quack (n.2)
duck sound, 1839, from quack (v.).
例文
1. Why do intelligent people find quack remedies so appealing？
なぜ賢い人は江湖の医術に惹かれるのか？
2.Suddenly heard a quack .
彼は突然ガラガラという叫び声を聞いた。
3.He describes himself as a doctor,but I feel he is a quack .
彼は医者だと自称しているが、私は彼が江湖の詐欺師だと感じている。
4.That doctor 's a quack ！
あの医者はヤブ医者だ！
5.For the rest it was just a noise，a quack - quack -quacking.