How to say "actor" in Arabic

Mumaththil is "one who represents, makes-similar" — from m-th-l, matching Hebrew משל (mashal, "proverb, parable, likeness") letter for letter (ث↔ש is regular). Arabic specialized the shared root toward performance — a mumaththil makes himself similar to a character, i.e. plays a role; Hebrew specialized it toward rhetoric — a משל is a verbal comparison, a parable. Different professions, same root idea of resemblance.