Le cas échéant = In such a case; If such should be the case.
C’est le cas ou jamais = It is now or never.
Nous en faisons grand cas = We value it very highly.
Tout mauvais cas est niable = A man may be expected to deny a deed that he knows to be wrong.
Un en-cas = Something prepared in case of need.
[Formerly this was said of a slight meal placed in a bedroom in case one should wake in the night and need food. Now it rather refers to anything that can be used in case guests arrive unexpectedly. Also of a parasol that can be used as an umbrella in case it rains. The latter is more usually called un en-tout-cas.]
Une noce à tout casser (pop.) = A rare old jollification.
Vous me cassez la tête avec votre bruit = You split my head with your noise.