Czym

Czym is the instrumental singular form of the Polish interrogative pronoun co, meaning "what." It is used to express means, instrument, or manner, and appears in both questions and subordinate clauses.

In Polish grammar, czym forms from the base co with the instrumental ending -ym. It is the form required by verbs and prepositions that govern the instrumental case. The most common constructions are with prepositions that take instrumental, such as z czym (with what) and with verbs that ask about means or tools, for example czym mogę ci pomóc (What can I help you with?).

Examples of usage include: Czym mogę ci pomóc? (What can I help you with?), Z czym masz problem? (What are you having a problem with?), Nie wiem, czym to jest (I don’t know what that is). In dependent clauses, czym can appear after a verb or conjunction that introduces a question or a specification about means or method.

Czym should not be confused with other forms of co (such as co in nominative or czego in genitive). It functions specifically as the instrumental form, commonly used in interrogative and relative constructions to indicate the means, instrument, or manner by which something is done.

In the grammar of Polish, czym is one of several case forms of the pronoun co, and its correct use depends on the governing preposition or verb that requires the instrumental case.