out of the blue
In real, traceable use. Part of the curated seed collection; community review is coming.
Where it’s used:
Used
Widespread English
Examples
Then once more out of the blue he said quietly, ‘ Are you elect?’
Why should he suddenly have materialized out of the blue?
British National Corpus sentence via the MAGPIE corpus (CC BY 4.0, retrieved 2026-07-30)
Sources & notes
Listed in Wiktionary’s “English idioms” category (retrieved 2026-07-29); definition pending editorial review. Figurative class: Metaphor (PIE-English corpus, CC BY 4.0, retrieved 2026-07-31).
Equivalents & related
Common questions
What does “out of the blue” mean?
By surprise.
Is “out of the blue” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.
What is the closest equivalent?
“tự dưng” (Tiếng Việt) — near equivalent.