Traditionally, pagan simply meant "people of/close to the Earth. Whether it was derogatory or not depended who was using it.
I have been given to understand that the concept of "pagan" predates the language the word pagan came from. It actually comes from "Adamic":times.
Adam and Eve were kicked out of the garden of Eden and condemned to work the Earth for their food because they had separated themselves from their "god". The other people who still maintained their "god" in and amongst themselves were still hunter-gatherers. Thus, "Adamic" people became "half people". It would have been derogatory because they struggled with the land whilst the others lived more in harmony with it; being nomadic with seasons.
Eventually most of humanity became "civilized"/"half people", however city dwellers still were those who did not struggle with the land. Abraham was separated out, becoming "pagan" but nomadic- shepards following grazing. They separated themselves from spirit again, choosing one god outside themselves and ridding themselves of idols.
Now, it is more typical for "whole people" to be away from the cities working the land, thus becoming the "pagans"😉