a toy consisting of a pair of joined discs with a deep groove between them in which string is attached and wound, which can be spun alternately downward and upward by its weight and momentum as the string unwinds and rewinds
悠悠球，溜溜球（一种玩具，由一对圆盘合成，两圆盘中间有一圈深槽，槽上绕细绳，圆盘因自身重量和冲力随细绳的卷起和松开而上下滚动）。
[often as modifier]a thing that repeatedly falls and rises again
反复上下起落的事物
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the yo-yo syndrome of repeatedly losing weight and gaining it again .不断减肥又不断反弹的反复症状。
〈非正式，主北美〉 笨蛋，疯子，变化无常的人。
move up and down; fluctuate
上下起落；波动
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popularity polls yo-yo up and down with the flow of events .民意调查显示的支持率随着事态的变化而上下波动。
[with obj.]manipulate or manoeuvre (someone or something)
摆布（某人）；操纵（事情）
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I don't want the job if it means he gets to yo-yo me around .如果那份工作意味着我将听凭他摆布的话，我就不想干了。
" early 20th cent.: of unknown origin．"