'Artifex' is used of any kind of artist, as opposed to artists adept in some particular field, as, e.g., 'pictor' ('painter'), 'sculptor' ('sculptor'), 'musicus' ('musician'), 'poeta' ('poet'), etc. It is a compound formed from the stem of 'ars' (i.e., 'arti-', meaning 'art, skill') and the suffix '-fex', derived from 'facere' ('to make, do'). The two substantives are standing in apposition and thus agree in case.