My young son is creating a costume and ancient roman identity for a school project.
In Latin, some possibilities are “proeliator/preliator” or “miles/militis” and in Greek, “polemistis.” If you’re looking to use the latin term (I don’t know Latin), I would guess the difference is between male or female.
There are different terms depending on the type of warrior or soldier. “Hoplite” is a term frequently used for soldiers in ancient Greece.