Quick Definition
nullification, abrogation
Strong's Definition
cancellation (literally or figuratively)
Derivation: from G114 (ἀθετέω);
KJV Usage: disannulling, put away
Thayer's Greek Lexicon
ἀθέτησις, (εως, ἡ (ἀθετέω, which see; like νουθέτησις from νουθετεῖν), abolition: Heb_7:18; Heb_9:26; (found occasionally in later authors, as Cicero, ad Att. 6, 9; Diogenes Laërtius 3, 39, 66: in the grammarians rejection; more frequently in ecclesiastical writings).
Mounce Concise Greek Dictionary
ἀθέτησις athetēsis 2x
abrogation, annulling, Heb_7:18 ; Heb_9:26
Abbott-Smith Greek Lexicon
† ἀθέτησις -εως , ἡ
( <ἀθετέω ),
[in LXX , usually of unfaithful, rebellious action: 1Sa_24:12 ( H6588 ), Jer_12:1 ( H899 ), ?? Dan_9:7 ( H4604 ) 2Ma_14:28 * ;]
a disannulling, setting aside: Heb_7:18 ; Heb_9:26 . (For similar usage in Papyri, v. Deiss., BS , 228 f .; MM , VGT , s.v. )†
Moulton & Milligan — Vocabulary of the Greek NT
ἀθέτησις [page 12]
The force of ἀθέτησις in Heb_7:18 ; Heb_9:26 is well brought out by Deissmann s reference ( BS p. 228 f.) to the technical legal formula in the papyri εἰς ἀθέτησιν καὶ ἀκύρωσιν , as in BGU I. 44 .16 (A.D. 102) τὴν δ [ια ]γραφὴν εἰς ἀθέτησιν καὶ ἀκύρωσιν , the decree to be annulled and cancelled. So P Amh II. 111 .19 f. (A.D. 132), P. Tebt II. 397 .12 (A.D. 198), P Saοd Khan 2 b14 (B.C. 22), etc.
STEPBible — Tyndale Abridged Greek Lexicon
ἀθέτησις, -εως, ἡ
(ἀθετέω), [in LXX, usually of unfaithful, rebellious action: 1Ki.24:12 (פֶּשַׁע), Jer.12:1 (בֶּגֶד), Da TH 9:7 (מַעַל), 2Ma.14:28 * ;]
a disannulling, setting aside: Heb.7:18 9:26 (for similar usage in π., see Deiss., BS, 228 f.; MM, VGT, see word).†
(AS)