Afterwards took a student to one side (7)
I believe the answer is:
lateral
'to one side' is the definition.
(I've seen this before)
'afterwards took a student' is the wordplay.
'afterwards' becomes 'later' (synonyms).
'took' says to put letters next to each other.
'student' becomes 'L' (as in L-plates for learner drivers).
'later'+'a'+'l'='LATERAL'
(Other definitions for lateral that I've seen before include "Shoot" , "Situated at or extending to the side" , "Edgeways" , "belonging to the side" , "Possibly right" .)