'arianistic' originates from Late Latin and Greek, specifically the proper name 'Arius' (the 4th-century presbyter whose teachings gave rise to Arianism) combined with the suffix '-istic' (from Greek '-istikos'), where 'Arius' is the name and '-istikos' meant 'pertaining to'.

'arianistic' developed in English by combining 'Arian' (from Latin 'Arianus', from the name 'Arius') with the adjectival suffix '-istic' (via Greek '-istikos'), so that the modern English adjective came from the name of the historical figure and a productive adjectival suffix.

Initially it referred specifically to things relating to Arius or his followers; over time it has been used more broadly to describe doctrines, opinions, or characteristics associated with Arianism (and sometimes used pejoratively to label heterodox beliefs).