Member finding a student of the law (5)
I believe the answer is:
legal
'of the law' is the definition.
'member finding a student' is the wordplay.
'member' becomes 'leg' (member can mean a limb).
'finding' is a charade indicator (letters next to each other).
'student' becomes 'L' (as in L-plates for learner drivers).
'leg'+'a'+'l'='LEGAL'
(Other definitions for legal that I've seen before include "Permitted by law" , "sanctioned" , "Sound" , "associated with silk business?" , "In accordance with statute" .)