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Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.

Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com
o who
Grammar usage guide and real-world examplesUSAGE SUMMARY
The phrase "o who" is not correct or usable in written English.
It appears to be a fragment and lacks clarity or context for proper usage. Example: "I was wondering, o who could help me with this task?"
⚠ May contain grammatical issues
News & Media
Arts
Science
Alternative expressions(4)
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Human-verified examples from authoritative sources
Exact Expressions
18 human-written examples
But just as important, it eats up time that would have been better served filling out the unemployed O, who never comes into focus.
News & Media
Mr O, who is represented in his action against the UK government by the London-based firm Leigh Day, claims he was violently evicted from his farm in the Gambella region in 2011.
News & Media
The list of the dead emerged when the Dutch government launched a war crimes investigation into Amanullah O – who was found to have run the secret police's investigation department.
News & Media
"I think exposure and competition are there, but that's the last think I want to think about," said Erica de la O, who earned a spot after being moved off the wait list in April.
News & Media
In front of the Big O, who once averaged a triple-double for a season, Kidd's throwback performance included 21 points, 10 rebounds and 13 assists, his fourth triple-double of the season.
News & Media
The auditorium fills with dry ice for Sunn O))) who are also dressed for holy orders but whose music, an hour and a half of relentless drone, is assault and battery with guitars.
News & Media
Human-verified similar examples from authoritative sources
Similar Expressions
42 human-written examples
Jack Lord, the deadpan star of "Hawaii Five-O" who made "Book him, Danno" a fixture of American slang, died Wednesday at his home in Honolulu.
News & Media
"This is La Taylor saying loud and clear, 'Don't you forget, Boy-o, who the star of this show really is,' " Burton says bitterly.
News & Media
Poe, who unlike the other prisoners is technically a free man, does actually get an opportunity to escape at this point, but turns it down because his prison cell chum Baby-O – who happens to be diabetic – is in dire need of insulin.
News & Media
I had planned to spend my first night off with my seven month old baby but went instead to meet Steve-O who insisted we do Tequila slammers and then proceeded to snort the salt up his nose and squeeze the lemon into his eye.
News & Media
One man seemingly not joining the keeper in looking to the long-term at the Bernabéu is I-S-C-O, who would like to be set free to roam where he wants, which might turn out to be a club in England.
News & Media
Expert writing Tips
Best practice
Avoid using "o who" in formal writing. Instead, opt for grammatically correct alternatives like "oh who" or rephrase the sentence for clarity.
Common error
Don't confuse the interjection "oh" with the single letter "o". "Oh" expresses surprise or realization, while "o" alone lacks a clear grammatical function in most modern contexts. Consider rephrasing for clarity.
Source & Trust
85%
Authority and reliability
2.5/5
Expert rating
Real-world application tested
Linguistic Context
The phrase "o who" functions questionably as an interrogative phrase. As Ludwig indicates, it's not considered correct in contemporary English. Grammatically, it is not standard.
Frequent in
News & Media
33%
Arts
33%
Science
33%
Less common in
Formal & Business
0%
Encyclopedias
0%
Wiki
0%
Ludwig's WRAP-UP
The phrase "o who" presents a unique case in modern English. While it appears in some sources, including news and media, Ludwig highlights its grammatical incorrectness and infrequent usage. As an interrogative phrase, its function is to ask about someone's identity, but it's better to opt for grammatically sound alternatives like "oh who", "who is it", or "who could it be". Due to its ambiguity and lack of standardization, it's advisable to avoid "o who" in formal writing and communication.
More alternative expressions(10)
Phrases that express similar concepts, ordered by semantic similarity:
oh who
Adds an 'h' to 'o', creating a more common interjection before the question.
who is it
Replaces the phrase with a direct question about identity.
who could it be
Expresses wonder or speculation about someone's identity.
who is that
Similar to "who is it", but specifies a particular person being referenced.
who might that be
More formal and tentative way of asking "who is that".
who then
Emphasizes the question of 'who' in a sequence or selection.
whom
Uses the correct grammatical form for the object of a verb or preposition if applicable.
well who
Adds 'well' to express slight surprise or impatience before the question.
so who
Implies previous discussion and the need to clarify the person.
and who
Similar to 'so who', but implies a connection to a previous statement.
FAQs
What's the correct way to start a question with 'o'?
Using just "o" before a question word like "who" is generally incorrect. You might want to use "oh who" as an interjection expressing surprise or realization, but it's better to rephrase for clarity.
What can I say instead of "o who" to ask about someone's identity?
Instead of "o who", use phrases like "who is it", "who is that", or "who could it be" for clarity.
Is "o who" grammatically correct?
No, "o who" is not generally considered grammatically correct in modern English. It's better to use a grammatically sound alternative.
When might I encounter the phrase "o who"?
You might encounter "o who" in older texts or poetry, where the use of "o" as a direct address or exclamation was more common. However, it's rarely used in contemporary writing.
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Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Source & Trust
85%
Authority and reliability
2.5/5
Expert rating
Real-world application tested