This is the 5575th most frequent Dutch word.
mattijs
"Mattijs" is not a standard Dutch word. It might be a misspelling or a proper noun, such as a name.
In this sentence, 'Mattijs' serves as a proper noun, specifically a person's name, and is the subject of the sentence.
Mattijs kwam naar het feest en bracht een cadeau mee.
Mattijs came to the party and brought a gift.
'Mattijs' is used as a proper noun, indicating a specific person who is being referred to in the conversation.
Heb jij Mattijs al laten weten over de nieuwe plannen?
Have you informed Mattijs about the new plans yet?
'Mattijs' here fulfills the role of a proper noun representing the person whom the speaker met, and is the object in the clause of the sentence.