n.
  - a mass of small bubbles in liquid caused by agitation, fermentation, or salivating. ▸impure matter that rises to the surface of liquid. 
- worthless or insubstantial talk, ideas, or activities.
v.
 form, produce, or contain froth.
Derivative
  
    - frothily adv.
- frothy adj. (frothier, frothiest) .
 
  Etymology
  ME: from ON frotha, frauth.