Instead of explaining the truth to FranC, you posted false information,
They are all the same word, but conjugated to express different parts of speech! γνόντεσ is the active aorist participle of the cognate verb γινώσκω, the form of the word found in lexicons.
The word ‘know’ in Rom. 1: 21 does not mean “to perceive or realize;” it means “to arrive at a knowledge of someone or something, know about, make acquaintance of” (A Greek-English Lexicon of the New Testament and other Early Christian Literature, Third Edition, The University of Chicago Press, 2000.
Examples of this usage include the following,
Rom. 1:21. διότι γνόντες τὸν Θεὸν οὐχ ὡς Θεὸν ἐδόξασαν ἢ εὐχαρίστησαν, ἀλλ᾿ ἐματαιώθησαν ἐν τοῖς διαλογισμοῖς αὐτῶν, καὶ ἐσκοτίσθη ἡ ἀσύνετος αὐτῶν καρδία·
Rom. 1:21. For even though they knew God, they did not honor Him as God or give thanks, but they became futile in their speculations, and their foolish heart was darkened.
γνόντεσ is the active aorist participle of the cognate verb γινώσκω. The form of the word found in lexicons. γινώσκω is used three times in John 14:7,
John 14:7. εἰ ἐγνώκειτέ με, καὶ τὸν πατέρα μου γνώκειτε ἄν. καὶ ἀπ᾿ ἄρτι γινώσκετε αὐτὸν καὶ ἑωράκατε αὐτόν.
John 14:7. “If you had known Me, you would have known My Father also; from now on you know Him, and have seen Him.” (NASB, 1995)
It is also used in John 17:3,
John 17:3 αὕτη δέ ἐστιν ἡ αἰώνιος ζωή, ἵνα γινώσκωσι σὲ τὸν μόνον ἀληθινὸν Θεὸν καὶ ὃν ἀπέστειλας ᾿Ιησοῦν Χριστόν.
John 17:3. “This is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent.” (NASB, 1995)
It is also used in 2 Cor. 5:16,
2 Cor. 5:16 ῞Ωστε ἡμεῖς ἀπὸ τοῦ νῦν οὐδένα οἴδαμεν κατὰ σάρκα· εἰ δὲ καὶ ἐγνώκαμεν κατὰ σάρκα Χριστόν, ἀλλὰ νῦν οὐκέτι γινώσκομεν.
2 Cor. 5:16. Therefore from now on we recognize no one according to the flesh; even though we have known Christ according to the flesh, yet now we know Him in this way no longer. (NASB, 1995)
To which you replied,
They are all the same word, but conjugated to express different parts of speech! γνόντεσ is the active aorist participle of the cognate verb γινώσκω, the form of the word found in lexicons.