Describing people precisely

The list ends on perdre son sang-froid, and the picture inside it points the other way in English. Le sang-froid is the composure of somebody whose pulse does not rise: garder son sang-froid is to keep a cool head, faire preuve de sang-froid is what a report says of the driver who avoided the accident, and perdre son sang-froid, the entry here, is to lose all of that. Cold blood is entirely to the person’s credit. English borrowed the phrase whole and still spelled as in French, and that borrowing kept the admiring sense; but the home-made version, « in cold blood », went the other way and settled on premeditation — on the killer who was not carried away by anything. So one image praises a man and condemns another, and neither form will do the other’s work: « he kept his cold blood » is not English, and the sentence wants « cool » or « head » instead. One honest complication: tuer de sang-froid exists in French too, with exactly the English meaning. It is the noun with an article that praises, and the bare adverbial phrase that accuses.