Literal Translation
To do white cabbage
Actual Meaning
To fail (especially when looking for something or investigating)
Etymology
This has nothing to do with the vegetable, even though there is a variety of cabbage that is white! Here, chou(p) refers to a shot, pronounced ‘à la berrichonne’ since the expression originated in the Berry region. Is might because the name chou comes from the Latin caulis that the [k] sound has been retained in the dialect? Anyway, in skittles, a c[h]oup blanc was a null shot, with no result. ‘Faire chou blanc’ therefore means to fail.