Green on back of course to turn outwards (5)
I believe the answer is:
evert
'turn outwards' is the definition.
(to evert is to turn inside out)
'green on back of course' is the wordplay.
'green' becomes 'vert' (I've seen this before).
'on' says to put letters next to each other.
'back' indicates one should take the final letters (I've seen 'back of' mean this).
The final letter of 'course' is 'e'.
'vert' after 'e' is 'EVERT'.
'to' is the link.
(Other definitions for evert that I've seen before include "Turn aside or outwards" , "Tennis champion" , "Former US World No 1 tennis player, b. 1954" , "arrange to have the wrong side out?" , "Chris - - (women's tennis)" .)