'no one' is primarily used as a pronoun in English. It refers to not a single person or not anyone. As a pronoun, 'no one' is used to indicate the absence of any person or to emphasize the lack of participation or presence of any individual in a particular situation or context.
'no one' is always two separate words. It should not be confused with 'noone,' which is incorrect. It is synonymous with 'nobody,' though 'no one' can sometimes be seen as slightly more formal. 'No one' is singular and therefore takes a singular verb.
No one knows the answer to that riddle.
No one came to the party, which was quite disappointing.
She looked around, but no one was in sight.
a common mistake is writing 'noone' instead of 'no one.' Always ensure there's a space between the two words. Be careful with verb agreement. Since 'no one' is singular, it should be followed by a singular verb, e.g., 'No one is coming to the event.' 'No one' can be emphasized with 'else' as in 'No one else can do it,' meaning that out of everyone, only a specific person can do it.