英语词源字典 - 在线词源网站

flexible (adj.)[flexible 词源字典]: early 15c., "capable of being bent; mentally or spiritually pliant," from Middle French flexible or directly from Latin flexibilis "that may be bent, pliant, flexible, yielding;" figuratively "tractable, inconstant," from flex-, past participle stem of flectere "to bend," which is of uncertain origin. Flexile (1630s) and flexive (1620s) have become rare. Related: Flexibly. Coles' dictionary (1717) has flexiloquent "speaking words of doubtful or double meaning."[flexible etymology, flexible origin, 英语词源]
inflexible (adj.): late 14c., "incapable of being bent, physically rigid," also figuratively, "unbending in temper or purpose," from Middle French inflexible and directly from Latin inflexibilis, from inflexus, past participle of inflectere (see inflect). In early 15c. an identical word had an opposite sense, "capable of being swayed or moved," from in- "in, on." Related: Inflexibly.
skateboard: 1964, noun and verb, from skate (v.) on model of surfboard. The phenomenon began c. 1963 in southern California and was nationwide the following summer.
Skateboarding requires only a tapered piece of wood flexibly mounted on roller-skate wheels and a stretch of pavement -- preferably downhill and away from traffic. ["Life," June 5, 1964]