a. [ Compar. Frothier superl. Frothiest. ] 1. Full of foam or froth, or consisting of froth or light bubbles; spumous; foamy. [ 1913 Webster ]
2. Not firm or solid; soft; unstable. Bacon. [ 1913 Webster ]
3. Of the nature of froth; light; empty; unsubstantial; as, a frothy speaker or harangue. Tillotson. [ 1913 Webster ]