A primitive root; to be untrue, in word (to lie, feign, disown) or deed (to disappoint, fail, cringe) -- deceive, deny, dissemble, fail, deal falsely, be found liars, (be-)lie, lying, submit selves.
כָּחַשׁ verb be disappointing, deceive, fail, grow lean (Late Hebrew כָּחַשׁ grow lean; Hiph`il convict of falsehood, refute; Aramaic כְּחַשׁ grow lean; כַּחְשָׁא leanness, כְּחִישׁוּתָא leanness, weakness; Aph`el as Late Hebrew Hiph`il) —
Qal. Perfect3masculine singular מִשָּׁ֑מֶן כָּחַשׁ וּבְשָׂרִי Psalm 109:24 my flesh hath grown lean (away) from fatness ("" מִצּוֺם כָּֽשְׁלוּ בִּרְכַּי).
Niph`al Imperfect לָךְ אֹיְבֶיךָ וְיִכָּֽחֲשׂוּ Deuteronomy 33:29 thine enemies shall cringe (come cringing, i.e. originally act deceptively, feigning obedience) to thee (compare also Pi`el 3, Hithpa`el)
Pi`el Perfect3masculine singular כִּחֵשׁ 1 Kings 13:18; Habakkuk 3:17; וְכִּ֫חֶשׁ consecutive (before monosyll.) Leviticus 5:22; Job 8:18, etc.; Imperfect (בָּהּׅ יְכַ֫חֶשּׁ Hosea 9:2-3;feminine singular וַתְּכַחֵשׂ Genesis 18:15, etc.; Infinitive absolute כַּחֵשׁ Hosea 4:2; Isaiah 59:13; construct Zechariah 13:4; —
1 device, absolute Genesis 18:15 (J), Joshua 7:11 (JE), Hosea 4:2 (וכחשׁ אלה together = false swearing according to WeKl. Pr.; + וְנָאֹ֑ף וְגָנֹב וְרָצֹחַ), compare בַּעֲמִיתוֺ אִישׁ תְשַׁקְּרוּ וְלֹא תְכַחֲשׁוּ וְלֹאֿ תִגְנֹ֑בוּ לֹא Leviticus 19:11 (H); כ ׳לְמַעַן Zechariah 13:4 in order to deceive; followed by לְ person 1 Kings 13:18; Job 31:28; followed by בְ person and of thing Leviticus 5:21, בְ of thing Leviticus 6:22.
2 act deceptively against (i.e. seem to acknowledge, but not really do so), followed by בְ person Joshua 24:27 (E), Jeremiah 5:12; Isaiah 59:13; Job 8:18, apparently also יכ ׳וְתִירוֺשׁ בָּהּ Hosea 9:2 and new wine shall deny her (Israel; i.e. refuse to acknowledge her as its mistress, not yield itself to her); absolute Proverbs 30:9.