The most common and most likely answer to this crossword clue is the 8 letter word CLEAVING
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More clues leading to the result CLEAVING
Buddy explains!

The straight part
We know that "Splitting" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case splitting = cleaving.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CLEAVING mean?
CLEAVING verb- To split or sever something with, or as if with, a sharp instrument.
- To break a single crystal (such as a gemstone or semiconductor wafer) along one of its more symmetrical crystallographic planes (often by impact), forming facets on the resulting pieces.
- To make or accomplish by or as if by cutting.
- To split (a complex molecule) into simpler molecules.
- To split.
- Of a crystal, to split along a natural plane of division.
- To cling, adhere or stick fast to something; used with to or unto.
- The act of one who cleaves, splits, or severs.
- The act of one who cleaves, clings, or adheres.