yo-yo

 
Pronunciation: /ˈjəʊjəʊ/
( trademark in the UK)

noun (plural yo-yos)

  • 1a 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: with a flick of the wrist, she sent the yo-yo spiraling down and watched it spin there
  • [often as modifier] a thing that repeatedly fluctuates: the yo-yo syndrome of repeatedly losing weight and gaining it again
  • 2 informal, chiefly North American a stupid, insane, or unpredictable person: they think they’re tangling with some small-town yo-yos, but they’re not

verb (yo-yoes, yo-yoing, yo-yoed)

[no object, usually with adverbial of direction]
  • move up and down; fluctuate: popularity polls yo-yo up and down with the flow of events
  • [with object] manipulate or manoeuvre (someone or something): I don’t want the job if it means he gets to yo-yo me around

Origin:

early 20th century: probably ultimately from a language of the Philippines