Synonyms 4. quiver. 5.Waver,fluctuate,vacillate refer to an alternation or hesitation between one direction and another. Waver means to hesitate between choices: to waver between two courses of action. Fluctuate suggests irregular change from one side to the other or up and down: The prices of stocks fluctuate when there is bad news followed by good. Vacillate is to make up one's mind and change it again suddenly; to be undecided as to what to do: We must not vacillate but must set a day.
c.1280, weyveren, "to show indecision," probably related to O.E. wæfre "restless, wavering," from P.Gmc. *wæbraz (cf. M.H.G. wabern "to waver," O.N. vafra "to hover about"), a frequentative form from the root of wave (v.).