Meaning

noun the period of greatest prosperity or productivity

noun a rosy color (especially in the cheeks) taken as a sign of good health

noun sudden brief sensation of heat (associated with menopause and some mental disorders)

originFrom Middle English flusshen, fluschen, of uncertain origin. Compare dialectal flusk (“to fly at, startle a bird out of the bush”) and flusker (“to flutter, fly irregularly”). Perhaps related to Middle English flasshen, flasschen, flaschen, see flash; or a Middle English blend of flowen (“to flow”) + guschen (“to gush”). Compare Saterland Frisian flutskje, German Low German flutschen, German…

Etymology from Wiktionary, CC BY-SA 3.0