out of the blue

💡 Meaning

Something that happens suddenly and unexpectedly, with no warning.

아무런 예고 없이 갑자기 예상치 못하게 일어나는 것을 말해요.

🧠 Memory Hook

Picture a perfectly clear blue sky — calm, quiet, no clouds at all. Suddenly, out of nowhere, a bolt of lightning strikes. Nothing gave any warning. That unexpected jolt is something coming out of the blue.