Exam is a sort of joke (9)
I believe the answer is:
practical
This clue is a double definition.
'exam' is the first definition.
(I've seen this before)
'a sort of joke' is the second definition.
(I've seen this before)
'is' is the link.
(Other definitions for practical that I've seen before include "Exam" , "Functional, pragmatic" , "Effective; virtual" , "Pragmatic, hard-nosed" , "Down to earth - like Eliot's Cats" .)