Mother and father split (6)
I believe the answer is:
parent
'mother' is the definition.
(I've seen this in other clues)
'father split' is the wordplay.
'father' becomes 'pa' (pa is a kind of father).
'split' becomes 'rent' ('rent' can be a synonym of 'split').
'pa'+'rent'='PARENT'
'and' is the link.
(Other definitions for parent that I've seen before include "Pa or Ma" , "old man?" , "What mums and dads do" , "One raises issue" , "Mum or dad" .)