The Collaborative International Dictionary of English v.0.48:

Frothy \Froth"y\, a. [Compar. Frothier; superl. Frothiest.]
   1. Full of foam or froth, or consisting of froth or light
      bubbles; spumous; foamy.
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   2. Not firm or solid; soft; unstable. --Bacon.
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   3. Of the nature of froth; light; empty; unsubstantial; as, a
      frothy speaker or harangue. --Tillotson.
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