# out of the blue

> English word · Prep_phrase · IPA /aʊt ɒv ðə bluː/

## Definitions
1. Unexpectedly; without warning or preparation.

## Etymology
Short for out of the blue sky, likening an unexpected event to lightning or rain coming suddenly from a cloudless sky.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/out-of-the-blue