lev·i·ty /ˈlɛvəti/
  輕率,輕浮,輕薄
  Lev·i·ty n.
  1. The quality of weighing less than something else of equal bulk; relative lightness, especially as shown by rising through, or floating upon, a contiguous substance; buoyancy; -- opposed to gravity.
     He gave the form of levity to that which ascended; to that which descended, the form of gravity.   --Sir. W. Raleigh.
     This bubble by reason of its comparative levity to the fluidity that incloses it, would ascend to the top.   --Bentley.
  2. Lack of gravity and earnestness in deportment or character; trifling gayety; frivolity; sportiveness; vanity. “ A spirit of levity and libertinism.”
     He never employed his omnipotence out of levity.   --Calamy.
  3. Lack of steadiness or constancy; disposition to change; fickleness; volatility.
     The levity that is fatigued and disgusted with everything of which it is in possession.   --Burke.
  Syn: -- Inconstancy; thoughtlessness; unsteadiness; inconsideration; volatility; flightiness.
  Usage: -- Levity, Volatility, Flightiness. All these words relate to outward conduct. Levity springs from a lightness of mind which produces a disregard of the proprieties of time and place.Volatility is a degree of levity which causes the thoughts to fly from one object to another, without resting on any for a moment. Flightiness is volatility carried to an extreme which often betrays its subject into gross impropriety or weakness. Levity of deportment, of conduct, of remark; volatility of temper, of spirits; flightiness of mind or disposition.
  ◄ ►
  levity
       n 1: feeling an inappropriate lack of seriousness [ant: gravity]
       2: lightness of manner