yo-yo

• n. 溜溜球（一种线轴般的玩具）；优柔寡断
• adj. 上下起落的；摇摆不定的
• vi. 摇摆不定；上下起落

品牌名，来自菲律宾某语言。

yo-yo (n.)

1915, apparently from a language of the Philippines. Registered as a trademark in Vancouver, Canada, in 1932, the year the first craze for them began (subsequent fads 1950s, 1970s, 1998). The toy itself is much older and was earlier known as bandalore (1802), a word of obscure origin, "but it was from American contact in the Philippines that the first commercial development was established" [Century Dictionary]. Figurative sense of any "up-and-down movement" is first recorded 1932. Meaning "stupid person" is recorded from 1970. The verb in the figurative sense is attested from 1967.