err on the side of

Verb

err on the side of (third-person singular simple present errs on the side of, present participle erring on the side of, simple past and past participle erred on the side of)

1. (idiomatic, transitive) To behave in a manner which favours or which is biased toward.
   • Every man would prefer that the woman in whom he feels an interest should err on the side of bigotry rather than on that of what is called liberalism in points of religious belief.1849, James Fenimore Cooper, chapter 15, in The Sea Lions
   • My case is, as I have told you, almost complete; but we must not err on the side of over-confidence.1890 February, A[rthur] Conan Doyle, “Sherlock Holmes Gives a Demonstration”, in The Sign of Four (Standard Library), London: Spencer Blackett […], →OCLC, page 89
2. To choose which mistake (err) will be perpetuated when all available options would result in different mistakes.