Supporter on course initially tackling English exam (3)
I believe the answer is:
tee
'supporter on course' is the definition.
(a tee supports a ball on a golf course)
'initially tackling english exam' is the wordplay.
'initially' indicates taking the first letters.
The initial letters of 'tackling english exam' is 'TEE'.
(Other definitions for tee that I've seen before include "Golfer drives from it" , "Golfing equipment" , "Starting peg" , "Start of a hole in golf" , "Golfer's support" .)