About to go and split (6)
I believe the answer is:
cleave
'split' is the definition.
(I know that split can be written as cleave)
'about to go' is the wordplay.
I cannot quite understand how this works, but
'about' could be 'c' (abbreviation for 'circa') and 'c' is found within the answer.
'go' could be 'leave' (leaving is a kind of going) and 'leave' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'and' is the link.
Can you help me to learn more?
(Other definitions for cleave that I've seen before include "Split or cling to" , "Divide by chopping, or cling" , "Fissure" , "Chop or stick to" , "Adhere - or chop as with axe" .)