Gnaw (4)
(Other definitions for bite that I've seen before include "(Of fish) take the bait" , "Small amount to eat" , "Use one's teeth" , "Get teeth into" , "Nip; nibble" .)
'gnaw' is the definition.
(I know that chew is the is a more specific form of the action of gnaw.)
This is all the clue.
(Other definitions for chew that I've seen before include "Bite repeatedly" , "Treat for dog" , "bit of tobacco" , "Work between teeth, masticate" , "Try to eat" .)