Breakdown of On jest całkowicie rozczarowany wszystkim.
być
to be
on
he / it (m)
wszystko
everything
całkowicie
completely
Questions & Answers about On jest całkowicie rozczarowany wszystkim.
Why does wszystkim take the instrumental case here, and why is there no preposition like z?
The word rozczarowany (disappointed) dictates the case of the object that follows it. In Polish, you express being disappointed 'by' something using the plain instrumental case, so it is rozczarowany wszystkim without a preposition. Adding z would incorrectly mean 'disappointed accompanied by everything'.
What is the dictionary form of wszystkim and does it share this form with other cases?
Wszystkim is the instrumental case of the pronoun wszystko (everything). This exact same word form is also used for the dative case (to everything) and the locative case (about everything), which you will see in other contexts.
I thought the verb jest (is) requires the instrumental case. Why is rozczarowany in the nominative?
The verb być (to be) takes the instrumental case when followed by a noun, for example: On jest nauczycielem (He is a teacher). However, when followed by an adjective or a participle like rozczarowany, it takes the nominative case so that it agrees directly with the subject On.