out of the blue

/aʊt ɒv ðə bluː/

//aʊt ɒv ðə bluː// prep_phrase

"out-of-the-blue" is a 12-letter English headword indexed on PlainSpell.

The verdict

“out of the blue” is uncommon English (outside the top frequency list), classed as a prep_phrase. The kind of spelling people second-guess.

Unranked
below top-frequency English
15
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Unexpectedly; without warning or preparation.

Key facts for out of the blue
PropertyValue
Headwordout of the blue
LanguageEnglish
Part of speechPrep_phrase
IPA/aʊt ɒv ðə bluː/
Letters15
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “out of the blue” sits in English frequency

out of the blue falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

out of the blue is uncommon English outside the top frequency list, classed as aprep_phrase, transcribed /aʊt ɒv ðə bluː/. Rarity is why readers land here mid-draft. Gloss: "Unexpectedly; without warning or preparation.".

The misspelling generator found no plausible variants for out of the blue, since its letter sequence doesn't invite the usual edit-distance slips. Our dataset records no confusable match here, which tends to mean the word is visually distinctive enough to stand on its own.

Etymologically, the entry records: Short for out of the blue sky, likening an unexpected event to lightning or rain coming suddenly from a cloudless sky. The correct English form is out of the blue, spelled O-U-T- -O-F- -T-H-E- -B-L-U-E.

Definition

  1. 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.

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "out of the blue"?
"out of the blue" is spelled O-U-T- -O-F- -T-H-E- -B-L-U-E. The IPA pronunciation is /aʊt ɒv ðə bluː/.
What does "out of the blue" mean?
As a prep_phrase, "out of the blue" means: Unexpectedly; without warning or preparation.
How do you pronounce "out of the blue"?
The IPA (International Phonetic Alphabet) transcription for "out of the blue" is /aʊt ɒv ðə bluː/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "out of the blue"?
Short for out of the blue sky, likening an unexpected event to lightning or rain coming suddenly from a cloudless sky. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “out of the blue”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is O-U-T- -O-F- -T-H-E- -B-L-U-E - every other letter order is a misspelling in standard orthography.
  • Say it as /aʊt ɒv ðə bluː/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list