Roget's Thesaurus of English Words and Phrases by Peter Mark Roget

320. Levity — N. levity; lightness &c adj.; imponderability, buoyancy,

volatility. feather, dust, mote, down, thistle, down, flue, cobweb, gossamer, straw, cork, bubble, balloon; float, buoy; ether, air. leaven, ferment, barm†, yeast. lighter-than-air balloon, helium balloon, hydrogen balloon, hot air balloon. convection, thermal draft, thermal. V. be light &c adj.; float, rise, swim, be buoyed up. render light &c adj.; lighten, leaven. Adj. light, subtile, airy; imponderous†, imponderable; astatic†, weightless, ethereal, sublimated; gossamery; suberose†, suberous†; uncompressed, volatile; buoyant, floating &c v.; portable. light as a feather, light as a thistle, light as air; lighter than air; rise like a balloon, float like a balloon SECTION II. INORGANIC MATTER