The Greek that is often translated as “judge” in English has the option of various terms in Luang with different shades of meaning.
For Acts 4:21 and 10:42, “maktorna wathudi lokarni-taitiaili lahanu” (“the one who holds the scales”). “This term is used when judgment of sin or wrong is in focus.”
For Acts 13:20, “maktorna deulu-tatra” (“the one who holds the law”). “This term is used for the judges in the Old Testament for whom judging wrong was only a part of their job.”
Source: Kathy Taber in Notes on Translation 1/1999, p. 9-16.
See also judge.