英语词源字典 - 在线词源网站

gofer (n.2)[gofer 词源字典]: "errand-runner," 1956, American English coinage from verbal phrase go for (coffee, spare parts, etc.), with a pun on gopher. Gopher also was late 19c. slang for a young thief, especially one who breaks in through small openings.[gofer etymology, gofer origin, 英语词源]
spare (adj.): "kept in reserve, not used, provided or held for extra need," late 14c., from or from the same root as spare (v.). Old English had spær "sparing, frugal." Also compare Old Norse sparr "(to be) spared." In reference to time, from mid-15c.; sense of "lacking in substance; lean, gaunt; flimsy, thin; poor," is recorded from 1540s. Spare part is attested from 1888. Spare tire is from 1894 of bicycles; 1903 of automobiles; 1961 of waistlines.