Dislike writing notes before exam (6)
I believe the answer is:
detest
'dislike' is the definition.
(to detest is to strongly dislike)
'notes before exam' is the wordplay.
'notes' becomes 'de' (two musical notes).
'before' means one lot of letters go next to another.
'exam' becomes 'test' (synonyms).
'de'+'test'='DETEST'
'writing' acts as a link.
(Other definitions for detest that I've seen before include "Be unable to stand" , "Dislike heartily" , "Find repulsive" , "Cordially dislike and loathe" , "Not like" .)