What is the meaning of frothing?

verb

• Become bubbly or frothy or foaming.
  • usage: "The boiling soup was frothing"; "The river was foaming"; "Sparkling water"
  • synonyms: foam, froth, fizz, effervesce, sparkle, form bubbles
• Make froth or foam and become bubbly.
  • usage: "The river foamed"
  • synonyms: froth, spume, suds
• Exude or expel foam.
  • usage: "the angry man was frothing at the mouth"
  • synonyms: froth

adjective

• Producing or covered with lathery sweat or saliva from exhaustion or disease.
  • usage: "the rabid animal's frothing mouth"
  • synonyms: foaming, foamy