Is there any common English word or expression to get across what is known in French as mauvaise foi a sort of mala fide? It describes, amongst other things, a situation where someone blatantly attempts to pass an error of their own off on someone else or otherwise claims to believe something they know to be false. A person acting in such a manner is said to be 'of bad faith' (literal translation). An example: You shake your head and tut-tut about the feckin' kids with their football when your wife finds the pieces of her favourite vase, moments after you put your hurley back in the hot press. Another: you bring a watch back to be repaired under guarantee saying it just stopped and there has been no water damage, although you just fished it out of the cistern an hour back. These aren't the best examples as they don't quite cover the scope of the expression, but should probably suffice. I know we say '(acting) in good faith' but does anyone use the opposite expression or any other one that conveys the same meaning. 'Dishonest' or 'hypocritical' don't quite cover it.