(out of the blue) informal (or out of a clear blue sky) Without warning; unexpectedly: she phoned me out of the blue [With reference to a ‘blue’ (i.e. clear) sky, from which nothing unusual is expected] Rarely does a profit warning come out of the blue like the subsequent share price reaction suggests. Quite frankly, this piece of research is so unexpected, so out of the blue, it beggars belief. This particular warning came out of the blue and there must be a worry that there is yet more to come. (purple patch) British informal A run of success or good luck: people expect me to score in every game now I’ve hit a purple patch (green with envy) Very envious or jealous. While the apartment was stunning and the attention to detail in the fittings and finishings faultless, it all paled in comparison to the view which was enough to make even your most critical guest green with envy.

"Out of the blue" means suddenly and unexpectedly ("I got a call out of the blue from my old classmate"). A "purple patch" is a British idiom meaning a period of good luck ("I've hit a purple patch at work: my last five sales have been successful"). To be "green with envy" means to be jealous or envious: in Shakespeare's "Othello," the villain Iago warns Othello to "beware of jealousy, my lord—it is a green-eyed monster.")