From the same as nekach; straightforward, i.e. (figuratively), equitable, correct, or (abstractly), integrity -- plain, right, uprightness.
see HEBREW nekach
H5228. nakoach
[נָכֹחַ] adjective and substantive straight, right, straightness, feminine נְכֹחָה, plural וֺת נְכֹחִים,-: — Isaiah 57:2 נְכֹחוֺ הֹלֵךְ he that walks in (compare 33:15; 50:10) his straightness (Ges 'der seinen geraden Weg geht'), figurative for straightforwardly (compare Proverbs 4:25); נְכֹחָה what is straight in front, figurative straightforwardness, honesty, Amos 3:10 נ עֲשׂוֺת יָָֽדְעוּ ׳לֹא, Isaiah 59:14 ׳ונ לָבוֺא תוּכַל לֹא ("" אֱמֶת); 2 Samuel 15:3 וּנְכֹחִים טובים דבריך thy pleadings are good and right (i.e. TRUE), Proverbs 8:9 (of words of Wisdom) לַמֵּבִין נְכֹחִים כֻּלָּם i.e. they lead straight to the right goal ("" ישׁרים; compare 8:8b וְעִקֵּשׁ נִפָתָּל בָּהֶם אֵין), 24:26 נְכֹחִים דְּבָרִים מֵשִׁיב i.e. either correct (leading to the right point), or honest answers; Isaiah 30:10 נְכֹחוֺת לָנוּ לֹאתֶֿחֱזוּ TRUE things (opposed to מַהֲתַלּוֺת חֲלָקוֺת, illusions), 26:10 יְעַוֵּל נְכֹחוֺת בְּאֶרֶץ in a land of rectitude (Che) he will do wickedly.