G0813
ἄτακτος
disorderly
ἀ-τακτος, -ον (τάσσω), [in LXX: 3Ma.1:19 * ;] out of order, out of place (Lat. inordinatus), frequently of soldiers not keeping the ranks, or an army in disarray (cf. 3Ma.1:19); hence, metaphorically, irregular, disorderly (see previous word): 1Th.5:14.† (AS)
Full Thayer's lexicon entry
ἄτακτος — átaktos
ἄτακτος, ἄτακτον (τάσσω), disorderly, out of the ranks, (often so of soldiers); irregular, inordinate (ἀτακτοι ἡδοναι immoderate pleasures, Plato, legg. 2, 660 b.; Plutarch, de book educ. c. 7), deviating from the prescribed order or rule: 1Th 5:14, cf. 2Th 3:6. (In Greek writings from (Herodotus and) Thucydides down; often in Plato.)
1 occurrence