We don't have synonyms for eques yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are equus, ques and equel.
(n) :
(historical, Ancient Rome) A member of the equestrian order (Latin: ordo equester), the lower of the two aristocratic classes of Ancient Rome, ranking below the patricians.
(n) :
(historical, Ancient Rome) A member of the equestrian order (Latin: ordo equester), the lower of the two aristocratic classes of Ancient Rome, ranking below the patricians.