古英語のcene, braveから、原語ゲルムネ語*kan, capableから、PIE*gno, to know, to understandから、語源的にはcan, knowから。
英語の語源
keen
keen: [OE] The ancestral meaning of keen is ‘brave’. That is what its German and Dutch relatives, kühn and koen, mean, and that is what keen itself meant in the Old English period. But this sense had died out by the 17th century, having been replaced by the meanings familiar today, such as ‘eager’ and ‘sharp’.
keen (adj.)
c. 1200, from Old English cene "bold brave," later "clever, wise," from Proto-Germanic *kan- "be able to" (see can). Original prehistoric senses seem to have been both "brave" and "skilled;" cognate with Old Norse k?nn "skillful, wise," Middle Dutch coene "bold," Dutch koen, Old High German kuon "pugnacious, strong," German kühn "bold, daring." Sense of "eager" is from mid-14c. The meaning "sharp" is peculiar to English: of blades and edges early 13c., of sounds c. 1400, of eyesight c. 1720. A popular word of approval in teenager and student slang from c. 1900.
keen (v.)
"lament," 1811, from Irish caoinim "I weep, wail, lament," from Old Irish coinim "I wail." Related: Keened; keening. As a noun from 1830.
例文
1. He 's been a keen supporter of the Labour Party all his life.
彼は一生労働党の熱烈な支持者だった。
2.We were very keen when the 1954 Rally came round.
1954年の集会が始まった時、私たちはとても熱烈だった。
3.He had retained a keen interest in the progress of the work.
彼はその仕事の進展に関心を持っていた。
4.The receivers are keen to sell the stores as one lot.
破産事務官は、これらの店舗をパッケージ化して全体的に販売しようとしている。
5.Detectives hunting the London bombers will be keen to interview him.