Back in the old days...things weren't as segregated socially as now. Separating "religion" from other aspects of culture and society is not so easy as in our modern notions of "separating church and state".
What was religious could also be economic, ecological, social... The person we would most likely call "priest" may also have been the closest thing to a "scientist" in a society such as that of Nazca.
I knew one "priest" who in Western society could also be labeled "doctor".
In Western languages we use the same word "priest" for those of the Roman Catholic Church as well as for those of pagan and other religions. Priests of Apollo, the Jewish Priesthood, etc. It's as good a word as any.
