Declining masculine acronyms
Polish declines administrative acronyms just like regular nouns. Common terms like ZUS (Social Insurance Institution), PIT (personal income tax), NIP (tax identification number), PESEL (national identification number), and VAT are vital for doing official paperwork.
Because these acronyms end in a spoken consonant, they act as masculine inanimate nouns. To decline them, attach the standard case endings using a hyphen (the acronym remains capitalized). For example, the Genitive takes -u and the Instrumental takes -em.
When dealing with taxes, you will frequently use the verbs rozliczać (imperfective) and rozliczyć (perfective), which mean to file or settle. You will also see the adjective skarbowy (tax / fiscal) for the tax office (urząd skarbowy) or tax official (urzędnik skarbowy).
Indeclinable acronyms: Feminine and plural
Acronyms ending in a vowel—like UE (the EU) and USA (the USA)—are generally indeclinable. Their spelling never changes and they do not take hyphens.
However, they still have an inherent gender based on the main noun of their full name:
- UE (Unia Europejska) is feminine because unia is feminine.
- USA (Stany Zjednoczone Ameryki) is plural because stany (states) is plural.
When an acronym is the subject of a sentence, the verb must match this inherent gender or number.