Privy to a student's course? (5)
I believe the answer is:
canal
'course?' is the definition.
(thesaurus)
'privy to a student's' is the wordplay.
'privy' becomes 'can' ('can' can be a synonym of 'privy').
'student' becomes 'l' (as in L-plates for learner drivers).
'can'+'a'+'l'='CANAL'
(Other definitions for canal that I've seen before include "eg Grand Union" , "Man-made watercourse" , "Manmade flower" , "Artificial waterway for barges" , "Man-made channel of water" .)