froth

(noun) a mass of small bubbles formed in or on a liquid. Synonyms: foam. Example: "The beer had a thick head of foam."

(verb) become bubbly or frothy or foaming. Synonyms: foam, fizz, effervesce, sparkle, form bubbles. Examples: "The boiling soup was frothing." "The river was foaming." "Sparkling water."

(verb) make froth or foam and become bubbly. Synonyms: spume, suds. Example: "The river foamed."

(verb) exude or expel foam. Example: "The angry man was frothing at the mouth."