1.verbTo crush with the teeth by repeated closing and opening of the jaws; done to food to soften it and break it down by the action of saliva before it is swallowed.
"Make sure to chew thoroughly, and don't talk with your mouth full!"
2.verbTo grind, tear, or otherwise degrade or demolish something with teeth or as with teeth.
"He keeps his feed in steel drums to prevent the mice from chewing holes in the feed-sacks."
3.verbTo think about something; to ponder; to chew over.
"The professor stood at the blackboard, chalk in hand, and chewed the question the student had asked."