Meaning

verb cause to fluctuate or move in a wavelike pattern

verb move or sway in a rising and falling or wavelike pattern

verb be unstable

originFirst attested in the 1630'; borrowed from Latin flūctuātus, perfect passive participle of flūctuō (“(of the sea) to surge, swell; (of man) to waver, fluctuate”), see -ate (verb-forming suffix) and -ate (adjective-forming suffix).

Etymology from Wiktionary, CC BY-SA 3.0