Crack from Split (4)
I believe the answer is:
snap
This clue is a double definition.
'crack' is the first definition.
('snap' can be a synonym of 'crack')
'split' is the second definition.
(thesaurus)
'from' is the link.
(Other definitions for snap that I've seen before include "you may take on holiday" , "Become unhinged" , "Break suddenly with cracking sound" , "Still" , "Bite at or utter angry words" .)