STRONGS NT 720: ἀρνέομαιἀρνέομαι, ἀρνοῦμαι; future ἀρνήσομαι; imperfect ἠρνουμην; 1 aorist ἠρνησαμην (rare in Attic, where generally ἠρνήθην, cf. Matth. i., p. 538 (better, Veitch, under the word)); perfect ή᾿ρνημαι; a deponent verb ((from Homer down)) signifying
1. to deny, i. e. εἰπεῖν ... οὐκ (to say ... not, contradict): Mark 14:70; Matthew 26:70; John 1:20; John 18:25, 27; Luke 8:45; Acts 4:16; followed by ὅτι οὐ instead of simple ὅτι, in order to make the negation more strong and explicit: Matthew 26:72; 1 John 2:22; (on the same use in Greek writings cf. Kühner, ii., p. 761; (Jelf, ii. 450; Winer's Grammar, § 65, 2 β.; Buttmann, 355 (305))).
2. to deny, with an accusative of the person, in various senses:
a. ἀρνουσθαι Ἰησοῦν is used of followers of Jesus who, for fear of death or persecution, deny that Jesus is their master, and desert his cause (to disown): Matthew 10:33; Luke 12:9; (John 13:38 L text T Tr WH); 2 Timothy 2:12 (ἀρνουσθαι τό ὄνομα αὐτοῦ, Revelation 3:8, means the same); and on the other hand, of Jesus, denying that one is his follower: Matthew 10:33; 2 Timothy 2:12.
b. ἀρνουσθαι God and Christ, is used of those who by cherishing and disseminating pernicious opinions and immorality are adjudged to have apostatized from God and Christ: 1 John 2:22 (cf. 4:2; 2 John 1:7-11); Jude 1:4; 2 Peter 2:1.
c. ἀρνουσθαι ἑαυτόν, to deny himself, is used in two senses, α. to disregard his own interests: Luke 9:23 (R WH marginal reading ἀπαρν.); cf. ἀπαρνέομαι. β. to prove false to himself, act entirely unlike himself: 2 Timothy 2:13.
3. to deny i. e. abnegate, abjure; τί, to renounce a thing, forsake it: τήν ἀσέβειαν καί τάς ἐπιθυμίας, Titus 2:12; by act to show estrangement from a thing: τήν πίστιν, 1 Timothy 5:8; Revelation 2:13; τήν δύναμιν τῆς εὐσεβείας, 2 Timothy 3:5. 4. not to accept, to reject, refuse, something offered: τινα, Acts 3:14; Acts 7:35; with an infinitive indicating the thing, Hebrews 11:24. (Compare: ἀπαρνέομαι.) 1>