We don't have synonyms for classman yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are classmate, clansman and chessman.
(n) :
(historical, UK, Oxford University) A candidate for graduation in arts who is placed in an honour class, as opposed to a passman, who is not classified.
(n) :
(historical, UK, Oxford University) A candidate for graduation in arts who is placed in an honour class, as opposed to a passman, who is not classified.