No one, nobody, nothing and nowhere are indefinite pronouns.
We use no one, nobody, nothing and nowhere to refer to an absence of people, things or places. We use them with a singular verb:
Nobody ever goes to see her. She’s very lonely.
You usually have to wait for a long time. Nothing happens quickly.
There was nowhere to park the car.
We often use the plural pronoun they to refer back to (singular) no one or nobody when we do not know if the person is male or female:
No one remembers the titles of the books they’ve read.
No one or nobody?
No one and nobody mean the same. Nobody is a little less formal than no one. We use no one more than nobody in writing:
I knew nobody at the party.
No one moved; no one said anything.
We write no one as two separate words or with a hyphen: no one or no-one but not
Nobody or not … anybody, etc.
Nobody, no one, nothing, nowhere are stronger and more definite than not … anybody/anyone/anything/anywhere:
I did nothing. (stronger than I didn’t do anything.)
She told no one, not even her mother. (stronger than She didn’t tell anyone …)
We don’t use not + anyone/anything/anywhere as the subject of a clause:
Nothing will make me change my mind.
Not anything will make me change my mind.
We don’t use nobody, no one, nothing, nowhere after no, not, never or other words which have a negative meaning (hardly, seldom). We use anyone, anybody, anything, anywhere:
I can’t do anything.
I can’t do nothing.
She talks to hardly anyone.
She talks to hardly no one.