Candidate from class rejected support on course (6)
I believe the answer is:
testee
'candidate' is the definition.
(I've seen this before)
'class rejected support on course' is the wordplay.
'class' becomes 'set' (I've seen this before).
'rejected' shows that the letters should be reversed in order.
'support on course' becomes 'tee' (golf tee on a golf course).
'set' written backwards gives 'tes'.
'tes'+'tee'='TESTEE'
'from' is the link.
(Other definitions for testee that I've seen before include "Someone taking exam" , "exam candidate" .)