Matthew 26:70ἠρνήσατο
But he denied it before them all: “I do not know what you are talking about.”
Luke 22:57ἠρνήσατο
But Peter denied it. “Woman, I do not know Him,” he said.
John 1:20ἠρνήσατο
He did not refuse to confess, but openly declared, “I am not the Christ.”
Acts 3:14ἠρνήσασθε
You rejected the Holy and Righteous One and asked that a murderer be released to you.
2 Timothy 2:12ἀρνησόμεθα
if we endure, we will also reign with Him; if we deny Him, He will also deny us;
1 John 2:22ἀρνούμενος
Who is the liar, if it is not the one who denies that Jesus is the Christ? This is the antichrist, who denies the Father and the Son.

Abbott-Smith

ἀρνέομαι -οῦμαι, depon.,
[in LXX: Gen.18:15 (כָּחַשׁ pi.), Wis.12:27 16:16 17:10, 4Ma.8:7 4Mac 10:15 * ;]

1. to deny, say no, opposite to είπεῖν: absol., Mat.26:70, Luk.8:45; before ἅτι, 1Jn.2:22; with inf., Heb.11:24

2. In late Gk. (MM, see word), with accusative of person(s), to deny, refuse to acknowledge, disown: Act.3:14 7:35; Ἰησοῦν, Mat.10:33, 2Ti.2:12, 1Jn.2:22, Ju 4; ἑαυτόν, Luk.9:23, 2Ti.2:13 (prove false to)

3. C. accusative of thing(s) (in cl. to refuse), to deny, abjure: 1Ti.5:8, Tit.2:12, 2Ti.3:5 (cf. ἀπαρνέομαι)
(AS)

Sources: Abbott-Smith’s Manual Greek Lexicon of the New Testament (1922, public domain) and glosses from STEPBible TBESG (CC BY 4.0); STEPBible TAGNT (Greek New Testament, CC BY 4.0); the Berean Standard Bible (public domain). Reformatted by Word Study, wording unchanged. All sources and licenses.