This is the 8224th most frequent Spanish word.
pastrnak
The word "pastrnak" is not Spanish; it may be a typo or from another language.
In this sentence, 'Pastrnak' is used as a proper noun referring to the individual David Pastrnak.
David Pastrnak es un jugador destacado de hockey.
David Pastrnak is an outstanding hockey player.
In this case, 'Pastrnak' functions as a possessive to indicate ownership of the jersey belonging to David Pastrnak.
La camiseta de Pastrnak se vendió rápidamente después del partido.
Pastrnak's jersey sold quickly after the game.
Here 'Pastrnak' is used as a noun representing a surname being analyzed linguistically.