It happened again.
Both 過ち（あやまち） and しくじり show up in my dictionaries as "mistake" or 失敗.
This does neither word any justice, as I saw an article list them as a matched set... isn't it redundant to list them separately if they have identical meanings ? (Let's ignore the case of "vim" and "vigor" for the moment...)
So, in an informal survey of some native speakers, I cobbled together some superior definitions and perhaps better match words than any dictionary seems to provide:
過ち: An error in judgement, or a moral failing. Doing the WRONG thing. "Misstep", "lapse of judgement", "transgression", "indiscrection", "crime", "sin" seems to be varying levels of seriousness which have the same general meaning.
しきじり: Failure to meet expectations, as in: not reaching a standard level of efficiency, quality, etc. This seems closer to "attempted but failed". "Failure" and "blunder" seem to be the closest meanings.
