Quick Definition
I smite, cut off, emasculate
Strong's Definition
to amputate; reflexively (by irony) to mutilate (the privy parts)
Derivation: from G575 (ἀπό) and G2875 (κόπτω);
KJV Usage: cut off
Thayer's Greek Lexicon
ἀποκόπτω: 1 aorist ἀπεκοψα; future middle ἀποκόψομαι; to cut off, amputate: Mar_9:43 (45); Joh_18:10; Joh_18:26; Act_27:32; ὄφελον καί ἀποκόψονται I would that they (who urge the necessity of circumcision would not only circumcise themselves, but) would even mutilate themselves (or cut off their privy parts), Gal_5:12. ἀποκόπτεσθαι occurs in this sense in Deu_23:1; (Philo de alleg. leg. 3:3; de vict. off. § 13; cf. de spec. legg. i. § 7); Epictetus diss. 2, 20, 19; Lucian, Eun. 8; (Dion Cass. 79, 11; Diodorus Siculus 3, 31), and other passages quoted by Wetstein (1752) at the passage (and Sophocles Lexicon under the word). Others incorrectly: I would that they would cut themselves off from the society of Christians, quit it altogether; (cf. Meyer and Lightfoot at the passage).
Mounce Concise Greek Dictionary
ἀποκόπτω apokoptō 6x
to cut off, Mar_9:43 ; Mar_9:45 ; Joh_18:10 ; Joh_18:26 ; Act_27:32 ;
to castrate, make a eunich, Gal_5:12
Abbott-Smith Greek Lexicon
ἀπο -κόπτω ,
[in LXX for H7112 , H3772 , etc.;]
to cut off: Mar_9:43 ; Mar_9:45 , Joh_18:10 ; Joh_18:26 Act_27:32 . Mid ., to mutilate oneself, have oneself mutilated: Gal_5:12 ( cf. Deu_23:1 LXX ; and v. Cremer , 751; MM , s.v. ).†
Moulton & Milligan — Vocabulary of the Greek NT
ἀποκόπτομαι (~ ἀποκόπτω ) [page 64]
On this word, taken in the sense of Deu_23:1 (supported by several instances in literary Κοινή see Grimm-Thayer) Nδgeli has some good remarks (p. 78 f.) : he brings together several phrases which show Paul using a more vernacular style in Gal than anywhere else, the startling passage 5 .12 being the climax Der zόrnende Apostel lδsst auch seiner Wortwahl freien Lauf; die stδrksten Ausdrόcke der Umgangsprache sind etzt die geeignetsten. Cf. Proleg. pp. 163, 201.
Liddell-Scott — Intermediate Greek Lexicon
ἀποκόπτω "to cut off, hew off", of men's limbs, Il. , Hdt. ; also, ἀπέκοψε παρήορον "he cut loose" the tracehorse, Il. :—Pass., ἀποκοπῆναι τὴν χεῖρα "to have" it "cut off", Hdt. ἀπ. τινὰ ἀπὸ τόπου "to beat off from" a strong place, Xen. Mid. "to smite the breast in mourning": c. acc. "to mourn for", νεκρόν Eur.
STEPBible — Tyndale Abridged Greek Lexicon
ἀπο-κόπτω
[in LXX for קָצַץ, כָּרַת, etc. ;]
to cut off: Mrk.9:43, 45, Jhn.18:10, 26 Act.27:32. Mid., to mutilate oneself, have oneself mutilated: Gal.5:12 (cf. Deu.23:1 LXX; and see Cremer, 751; MM, see word).†
(AS)