The Indefinite Pronoun некий (certain)

 

The Indefinite Pronoun некий (certain) (некая, некое, некие), is an indefinite pronoun.

The pronoun некий changes for gender, number and case and is used as an attribute; it is rarely used  in the oblique cases.

 

Приехал некий актёр.           

Some actor has come.

 

Выступала некая Сита.        

A certain Sita spoke.

 

The pronoun некий is generally used in the literary language.