From ek and dike; carrying justice out, i.e. A punisher -- a (re-)venger.
see GREEK ek
see GREEK dike
1. "without law and justice (cf. Latinexlex), unjust": Aeschylus, Sophocles, Euripides, Aelian n. an. 16, 5.
2. exacting penalty from (ἐκ) one; an avenger, punisher: Romans 13:4; περί τίνος, 1 Thessalonians 4:6; (Wis. 12:12; Sir. 30:6; 4 Macc. 15:26 (29); (Plutarch, de garrul. § 14, p. 509 f.); Herodian, 7, 4, 10 (5th edition, Bekker; others)).