Munch chop after chop, initially (4)
I believe the answer is:
chew
'munch' is the definition.
(to munch is to chew or bite)
'chop after chop initially' is the wordplay.
'chop' becomes 'hew' (I've seen this in another clue).
'after' says to put letters next to each other.
'initially' suggests taking the first letters.
The first letter of 'chop' is 'c'.
'hew' after 'c' is 'CHEW'.
(Other definitions for chew that I've seen before include "Reflect on" , "Treat for dog" , "Try to eat" , "Gnaw" , "bit of tobacco" .)