Definition
- C1
If something happens out of the blue, it occurs unexpectedly and without any prior indication.
意料之外地；突如其來地
He received a letter from an old friend out of the blue.
他出乎意料地收到了一位老朋友的信。
Their resignations came out of the blue, taking us all by surprise.
他們的辭職來得很突然，讓我們都感到驚訝。
I didn't expect him to do that at all; it was completely out of the blue.
我完全沒想到他會那樣做；這完全是出乎意料的。