Quick Definition
disorderly, slack
Strong's Definition
unarranged, i.e. (by implication) insubordinate (religiously)
Derivation: from G1 (Α) (as a negative particle) and a derivative of G5021 (τάσσω);
KJV Usage: unruly
Thayer's Greek Lexicon
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.)
Mounce Concise Greek Dictionary
ἄτακτος ataktos 1x
pr. used of soldiers, disorderly;
met. irregular in conduct, disorderly, lazy, 1Th_5:14
Abbott-Smith Greek Lexicon
** ἀ -τακτος , -ον
( < τάσσω ),
[in LXX : 3Ma_1:19 * ;]
out of order, out of place (Lat. inordinatus), freq . of soldiers not keeping the ranks, or an army in disarray ( cf. 3Ma_1:19 ); hence, metaph ., irregular, disorderly ( v. previous word): 1Th_5:14 .†
Moulton & Milligan — Vocabulary of the Greek NT
ἄτακτος [page 89]
See the discussion of ἀτακτέω . For the adj. (and adv.) we may quote P Fay 337 .16 f. (ii/A.D.) δεῖ τῶν [ἀν ]θρώπων ἄρχειν [τῶν ] πράξεων ἐκεί [νου ]ς δὲ εὐθὺς ἐφέπεσθαι , οὐκ ἀτάκτως μέντοι ἀλλ᾽ εἱμα [ρ ]μέ [νως : the document is a fragment of a philosophical work concerning the gods (Edd.). In Vettius Valens p. 336 .28 ἄτακτον φάσιν ἢ βελτίονα , the antithesis suggests a markedly bad meaning for ἄ . The same implication underlies the subst. in p. 116 .13 πολλὰ καὶ τῶν ἀτακτημάτων κρυβήσεται καὶ οὐκ ἔσται αἰσχρά which they would have been but for the kindly influence of Jupiter. The next sentence identifies the ἀτακτήματα as secret intrigues which will not be found out. In Syll 519 (see under ἀτακτέω ), where four sets of ἔφηβοι and their σωφρονισταί get their meed of praise and garlands, εὐτ ]άκτους αὑτοὺς παρέχουσιν replaces the verb in one place out of three. BGU IV. 1056 .13 (B.C. 13) διδόντες τὸν μὲν τόκον κατὰ μῆνα εὐτάκτως , regularly : so 1156 .14 (B.C. 15).
Liddell-Scott — Intermediate Greek Lexicon
ἄτακτος "not in battle-order", of troops, Hdt. , Thuc. , etc. "undisciplined, disorderly, irregular, lawless", id=Thuc. , etc. adv. -τως, "in an irregular, disorderly manner", of troops, id=Thuc. : comp. ἀτακτότερον, id=Thuc.
STEPBible — Tyndale Abridged Greek Lexicon
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)