This is the 142nd most frequent Ukrainian word.
щось
"Something."
In this case, 'щось' functions as a subject in the form of an indefinite pronoun specifying an unspecified object of interest.
Він намагається знайти щось цікаве для читання.
He is trying to find something interesting to read.
Here 'щось' is used to refer to a potential event or situation that is not clearly defined.
Якщо щось піде не так, я вас повідомлю.
If something goes wrong, I will inform you.
Here 'щось' is used as a pronoun to indicate an indefinite object that the speaker cannot specify.