This is the 111th most frequent Croatian word.
netko
"Netko" means "someone" or "somebody" in English.
Here, 'netko' is used as an indefinite pronoun denoting an unspecified individual, the object of the action intended by 'pozvati' (to invite).
Trebali bismo pozvati netko iz susjedstva.
We should invite someone from the neighborhood.
The word 'netko' functions as an indefinite pronoun meaning 'someone' in this sentence, used as the subject of the action.
Netko je ostavio vrata otvorena.
Someone left the door open.
In this interrogative sentence, 'netko' represents an indefinite person that the question refers to, emphasizing the search for an individual fitting the description offered in the relative clause.