1. The bubbles caused in fluids or liquors by fermentation or agitation; spume; foam; especially, 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.
(Science: zoology) froth insect, the cuckoo spit or frog hopper; called also froth spit, froth worm, and froth fly. Froth spit. See Cuckoo spit, under Cuckoo.
Origin: oe. Frothe, Icel. Frooa; akin to dan. Fraade, Sw. Fradga, as. Afreooan to froth.