Cool MateThey don't know who or what vs Unknown
When to use each in English, with meaning, register, and examples.
They don't know who or what
Top 2,000 (common)
Unknown
Top 2,000 (common)B2adjective
| They don't know who or what | Unknown | |
|---|---|---|
| Pronunciation | 🇬🇧 //ðeɪ doʊnt noʊ huː ɔr wɒt//🇺🇸 //ðeɪ doʊnt noʊ huː ɔr wɑt// | 🇬🇧 /["/ˌʌnˈnəʊn/"]/🇺🇸 /["/ˌʌnˈnəʊn/"]/ |
| Meaning | A phrase used to express uncertainty about a person or thing. | Not known or familiar. |
| Example | They don't know who or what will show up at the party. | The mysterious book contained many unknown secrets. |
| Register | Neutral | Neutral |
| How common | Top 2,000 (common) | Top 2,000 (common) |
| CEFR level | - | B2 |
| Part of speech | adjective | |
| Collocations | know who, know what, don't know | be, remain, completely, entirely, quite, to, for parts unknown, to parts unknown, for reasons unknown, be, remain, completely, entirely, quite, to, for parts unknown, to parts unknown, for reasons unknown, be, remain, completely, entirely, quite, to, for parts unknown, to parts unknown, for reasons unknown |
| Antonyms | - | known, familiar, certain |
| Common mistakes | Confusing with 'They don't know who' or 'They don't know what', which omit one part of the phrase., Misunderstanding the context, thinking it implies they know something., Omitting 'who' or 'what' entirely in casual conversation. | Confused with 'unkown' — incorrect spelling., Using it in a sentence where something is actually known., Misplacing it in a sentence making it unclear. |
| Usage notes | Used to convey that there is a lack of information about identity or nature. Common in both spoken and written English. | Used to describe something that is not recognized or identified. Commonly used in everyday conversation and writing. Avoid when the context is clear without it. |
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Frequently asked questions: They don't know who or what vs Unknown
What's the difference between They don't know who or what and Unknown?
They don't know who or what: A phrase used to express uncertainty about a person or thing. Unknown: Not known or familiar.
Can you show an example of each?
They don't know who or what: They don't know who or what will show up at the party. Unknown: The mysterious book contained many unknown secrets.
Can I use They don't know who or what and Unknown interchangeably?
Not always. They don't know who or what and Unknown are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.