The Collaborative International Dictionary of English v.0.48:

Froth \Froth\, v. t. [imp. & p. p. Frothed; p. pr. & vb. n..
   Frothing.]
   1. To cause to foam.
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   2. To spit, vent, or eject, as froth.
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            He . . . froths treason at his mouth. --Dryden.
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            Is your spleen frothed out, or have ye more?
                                                  --Tennyson.
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   3. To cover with froth; as, a horse froths his chain.
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