žvakati

1. to chew
   Ne žvaći otvorenih usta! — Don't chew with your mouth open!
   Stalno žvaće žvaku na času. — He's always chewing gum in class.
2. colloq. (of speech) to mumble
   Šta to žvaćeš, ništa te ne razumem. — What are you mumbling? I can't understand a thing.
3. colloq. derog. (of a topic, story) to keep rehashing; to harp on
   Stalno žvaću istu priču. — They keep rehashing the same story.

Perfective partners are «sažvakati» and «prožvakati».