Quick Definition
ἄτακτος, ον Adj 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
UBS Dictionary of the Greek New Testament
UBS Dictionary of the Greek New Testament © United Bible Societies, licensed CC BY-SA 4.0.
Thayer's Greek Lexicon
ἄτακτος, -ov, (τάσσω), disorderly, out of the ranks, (often so of soldiers); irregular, inordinate (ἄτακτοι ἡδοναί immoderate pleasures, Plat. legge. 2, 660 b.; Plut. de lib. educ. ο. 7), deviating from the prescribed order or rule: 1 Th. v. 14, cf. 2 Th. iii. 6. (In Grk. writ. fr. [Hdt. and] Thue. down; often in Plat.)
Mounce Concise Greek Dictionary
ἄτακτος ataktos 1x
pr. used of soldiers, disorderly; met. irregular in conduct, disorderly, lazy, 1 Thess. 5:14*
Abbott-Smith Greek Lexicon
** ἄ-τακτος, -ον
(< τάσσω), [in LXX: III Mac 1:19*;]
out of order, out of place (Lat. inordinatus), freq. of soldiers not keeping the ranks, or an army in disarray (cf. III Mac 1:19); hence, metaph., irregular, disorderly (v. previous word): I Th 5:14.†
Moulton & Milligan — Vocabulary of the Greek NT
ἄτακτος. See the discussion οἵ ἀτακτέω. For the adj. (and adv.) we may quote P Fay 337!6f (ii/A.p.) δεῖ τῶν [ἀν]ϑρώπων ἄρχειν [τῶν] πράξεων ἐκείί νου]ς δὲ εὐθὺς ἐφέπεσθαι, οὐκ ἀτάKTws μέντοι ἀλλ᾽ εἱμα[ρ])μέϊνως : the document is a fragment of “a philosophical work concerning the gods ” (Edd.). In Vettius Valens p. 33679 ἄτακτον φέσιν ἢ βελτίονα, the antithesis suggests a markedly bad meaning for & The same implication underlies the subst. in p. 1161 πολλὰ kal τῶν ἀτακτημάτων κρυβήσεται καὶ οὐκ ἔσται aloypa—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 Sy// 519 (see under ataktéw), 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!8 (B.c. 13) διδόντες τὸν μὲν τόκον κατὰ μῆνα εὐτάκτως, “regularly’’: so 115614 (B.C. 15).
Liddell-Scott-Jones — Greek-English Lexicon
ἄτακτος (ataktos) — disorderly. ἄτακτ-ος, ον, not in battle-order, of troops, [Refs 5th c.BC+]
2. not at one's post, [Refs 4th c.BC+]
II. undisciplined, disorderly, θόρυβος[Refs 5th c.BC+]; irregular, πυρετός[Refs 5th c.BC+]casual, [Refs]; of sensual excess, irregular, inordinate, ἡδοναί, Ἀφροδίτη, [Refs 5th c.BC+]; in Music, without rhythm, μελῳδίαι[Refs 3rd c.AD+]; in Medicine texts, irregular, σφυγμός[Refs 2nd c.AD+]
II.2. uncivilized, lawless, βίος[Refs 5th c.BC+]
II.3. in Mathematics texts, ἄτακτα προβλήματα indeterminate, not admitting of a definite solution, [Refs 5th c.AD+] __B adverb -τως in an irregular, disorderly manner, of troops, ἀ. καὶ οὐδενὶ κόσμῳ προσπίπτοντες[Refs 5th c.BC+] __B.2 irregularly, of fevers, [Refs 5th c.BC+] __B.3 comparative ἀτακτοτέρως somewhat negligently, [Refs 4th c.BC+]