dis-or'-der-li (ataktos): The word is found four times in the Epistles to the Thess (1Th 5:14; 2Th 3:6-7,11), "Withdraw yourselves from every brother that walketh disorderly."; "We behaved not ourselves disorderly."; "We hear of some that walk among you disorderly." The word is a military term and has reference to the soldier who does not keep the ranks (inordinatus, Liv). Then it refers to people who refuse to obey the civil laws, and thus it gets its meaning, "disorderly." It points to members in the early church, who, by their lives, became a reproach to the gospel of Christ (compare 1Th 4:11-12).
Henry E. Dosker