Informed about student jargon (5)
I believe the answer is:
slang
'jargon' is the definition.
(I know that jargon can be written as slang)
'informed about student' is the wordplay.
'informed' becomes 'sang' (I've seen this in other clues).
'about' indicates putting letters inside.
'student' becomes 'L' (as in L-plates for learner drivers).
'sang' going around 'l' is 'SLANG'.
(Other definitions for slang that I've seen before include "Vernacular" , "type of language?" , "common language" , "abuse" , "Non-standard vocabulary" .)