According to Samson Raphael Hirsch “keri” means “accident”.
“keri” derived from karah (see Commentary, Bereshis 24:12) – denotes anything that happens without intention or beyond our reckoning. Accordingly, it is a purely relative concept. Something in it self can be intentional and premeditated, yet we did not intend it or plan it; it just happened to us and came to us by chance….
Your going with Me is only keri. Your acting in accordance with My Will is not your only intention and is not the result of a decision on your part. Your foremost resolve is not to obey ME, not to do only My Will. You no longer are opposed to My Will as a matter of principle, but My Will is not important to you. Other considerations determine you way of life, and you leave it to chance whether this brings you into conflict or accord with Me. The troubles that befell Israel accomplished at least one thing; their defection ceased to be extreme opposition, directed – as a matter of principle – against God and His Torah. But heeding God is still not their first and only aim. The illusory interests of prosperity and power remain their primary concerns. Their walking with God remains incidental: they keep God’s commandments only if these happen to coincide with their own interests.
Baruch A. Levine writes in his commentary to Leviticus that the correct translation of “keri” is hostility. “Hebrew keri, “hostility” and the idiom halakh ‘im … be-keri, “to walk with … in hostility,” are unique to this chapter. Targum Onkelos translates be-kashyu, “with hardness, obstinacy” deriving keri from the root k-r-r, “to be cold.” Compare the noun form karah, “cold wave,” in Nahum 3:17, and mekerah, “cool chamber” in Judges 3:24
Shmuel David Luzzatto in his commentary to this verse, wonders why there is so much conjecture on the part of the commentators as to what keri means since, after all, Onkelos preceded them all and not only gives an obvious translation, but also clearly follows the translation that was accepted on the street, at the time. [I’m no expert in ShaDL, but he seems to take real offence at the mistranslation… he calls it a “perversion” עיוות )
“Nothing is farther from the Jewish concept of “MiKreh” than the idea of “chance”, with which it is usually taken to be associated.” Samson Raphael Hirsch on the verse
There is a clear bias against happenstance, serendipity, temporarily fealty, chance, accident, the unintentional, the unexpected, or as the King James translators put it in their notes as an alternative translation of “keri-contrary.” if ye walk at all adventures with me. (Leviticus 26: 21 King James Translators’ Notes)