Fool in book almost split symbol with stave (4,4)
I believe the answer is:
bass clef
'symbol with stave' is the definition.
(as in a bass clef on a musical stave)
'fool in book almost split' is the wordplay.
'fool' becomes 'ass' (both can mean a stupid person).
'in' is an insertion indicator.
'book' becomes 'bk' (abbreviation for book).
'almost' means to remove the last letter (most of the word but not all of it).
'split' becomes 'clef' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'bk' with its last letter removed is 'b'.
'b'+'clef'='bclef'
'ass' inserted inside 'bclef' is 'BASS CLEF'.
Can you help me to learn more?
(Other definitions for bass clef that I've seen before include "Pitch symbol on stave (music)" , "Musical notation with F on the fourth line of the stave" , "shower of pitch" , "Musical stave marking" .)