Sweet course not finished by bishop (8)
I believe the answer is:
syllabub
'sweet' is the definition.
(syllabub is a kind of sweet)
'course not finished by bishop' is the wordplay.
'course' becomes 'syllabus' (I've seen this before).
'not finished' means to remove the last letter.
'by bishop' becomes 'b' (abbreviation used in chess. I am not sure about the 'by' bit.).
'syllabus' with its last letter taken away is 'syllabu'.
'syllabu'+'b'='SYLLABUB'
(Other definitions for syllabub that I've seen before include "Sweetened cream beaten with liquor" , "Sweet creamy dessert" , "Whipped cream dessert flavoured with sherry or white wine" , "Cream dish" , "last part of meal?" .)