英语词源字典 - 在线词源网站

dun (v.)[dun 词源字典]: "to insist on payment of debt," 1620s, perhaps related to dunnen "to sound, resound, make a din" (c. 1200, dialectal variant of din), or shortened from dunkirk (c. 1600) "privateer," a private vessel licensed to attack enemy ships during wartime, from Dunkirk, French port from which they sailed. The oldest theory traces it to a Joe Dun, supposedly a London bailiff famous for catching defaulters. Related: Dunned; dunning. As a noun from 1620s.[dun etymology, dun origin, 英语词源]
lame duck (n.): 1761, "any disabled person or thing;" especially Stock Exchange slang for "defaulter."
A lame duck is a man who cannot pay his differences, and is said to waddle off. [Thomas Love Peacock, "Gryll Grange," 1861]
Sometimes also in naval use for "an old, slow ship." Modern sense of "public official serving out term after an election" is recorded by 1878 in American English, from an anecdote published in that year of President Lincoln, who is alleged to have said, "[A] senator or representative out of business is a sort of lame duck. He has to be provided for."