Have some gum (4)
I believe the answer is:
chew
'have some gum' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for chew that I've seen before include "Gnaw" , "work with canines" , "Bite repeatedly" , "Prepare to swallow" , "Bite and grind food in the mouth" .)