[yo-yo] n, pl yo-yos [perh. fr. a language of the Philippines] (1915) 1: a thick grooved double disk with a string attached to its center which is made to fall and rise to the hand by unwinding and rewinding on the string
2: one that resembles a yo-yo esp. in moving up and down unexpectedly or repeatedly
3: a stupid or foolish person
[2]yo-yo adj (1932): shifting back and forth or up and down uncertainly or unexpectedly [3]yo-yo vi yo-yoed ; yo-yo.ing (1967): to move from one position to another repeatedly: fluctuate