Froth n.
 1. The bubbles caused in fluids or liquors by fermentation or agitation; spume; foam; esp., a spume of saliva caused by disease or nervous excitement.
 2. Any empty, senseless show of wit or eloquence; rhetoric without thought.
    It was a long speech, but all froth.   --L'Estrange.
 3. Light, unsubstantial matter.
 Froth insect Zool., the cuckoo spit or frog hopper; -- called also froth spit, froth worm, and froth fly.
 Froth spit. See Cuckoo spit, under Cuckoo.