Beg cheese chopped up on board initially (7)
I believe the answer is:
beseech
'beg' is the definition.
(I've seen this in another clue)
'cheese chopped up on board initially' is the wordplay.
'chopped up' is an anagram indicator.
'on' says to put letters next to each other.
'initially' suggests taking the first letters.
The initial letter of 'board' is 'b'.
'cheese' anagrammed gives 'eseech'.
'eseech' put after 'b' is 'BESEECH'.
(Other definitions for beseech that I've seen before include "wood" , "Request earnestly" , "pray" , "Sue" , "Beg earnestly, plead" .)