Mean to go back to school with a boy (6)
I believe the answer is:
denote
'mean' is the definition.
(I know that denote is a type of mean)
'go back to school with a boy' is the wordplay.
'go back' says the letters should be written in reverse.
'to school' becomes 'Eton' (famous UK public school).
'with' says to put letters next to each other.
'a boy' becomes 'ed' (short for Edward).
'eton'+'ed'='etoned'
'etoned' backwards is 'DENOTE'.
'to' is the link.
(Other definitions for denote that I've seen before include "Be the sign or symbol of" , "Indicate, signify" , "Designate" , "Mean or signify" , "Stand as symbol for" .)