kangarooyoudaoicibaDictYouDict[kangaroo 词源字典]
kangaroo: [18] The first English speakers to refer in writing to the kangaroo were Captain Cook and the botanist Joseph Banks, who both mentioned it in 1770 in the journals they kept of their visit to Australia (Banks, for instance, referred to killing ‘kangaru’). This was their interpretation of ganjurru, the name for a large black or grey type of kangaroo in the Guugu Yimidhirr language of New South Wales.

English quickly generalized the term to any sort of kangaroo, although it caused some confusion among speakers of other Australian Aboriginal languages, who were not familiar with it: speakers of the Baagandji language, for instance, used it to refer to the horse (which had just been introduced into Australia). There is no truth whatsoever in the story that the Aboriginal word was a reply to the English question ‘What’s that?’, and meant ‘I don’t understand’.

The element -roo was used in the 19th century to produce jackeroo, which denoted ‘a new immigrant in Australia’, and is first recorded as an independent abbreviation of kangaroo in the first decade of the 20th century. The term kangaroo court ‘unofficial court’, which dates from the 1850s, is an allusion to the court’s irregular proceedings, which supposedly resemble the jumps of a kangaroo.
[kangaroo etymology, kangaroo origin, 英语词源]
kangaroo (n.)youdaoicibaDictYouDict
1770, used by Capt. Cook and botanist Joseph Banks, supposedly an aborigine word from northeast Queensland, Australia, usually said to be unknown now in any native language. However, according to Australian linguist R.M.W. Dixon ("The Languages of Australia," Cambridge, 1980), the word probably is from Guugu Yimidhirr (Endeavour River-area Aborigine language) /gaNurru/ "large black kangaroo."
In 1898 the pioneer ethnologist W.E. Roth wrote a letter to the Australasian pointing out that gang-oo-roo did mean 'kangaroo' in Guugu Yimidhirr, but this newspaper correspondence went unnoticed by lexicographers. Finally the observations of Cook and Roth were confirmed when in 1972 the anthropologist John Haviland began intensive study of Guugu Yimidhirr and again recorded /gaNurru/. [Dixon]
Kangaroo court is American English, first recorded 1850 in a Southwestern context (also mustang court), from notion of proceeding by leaps.