Learn Polish: Nasza firma zatrudnia ambitnych kandydatów. - Our company employs ambitious candidates.

Because kandydat refers to a male person. For masculine personal nouns (virile nouns), the Accusative plural copies the Genitive plural. That means the adjective takes the -ych ending and the noun takes -ów, giving us ambitnych kandydatów. If we were employing only women, it would be ambitne kandydatki.

Wait, isn't -ów the standard ending for the Genitive plural?

Yes, exactly! For masculine nouns, -ów is the Genitive plural ending. The special rule for masculine people is that their Accusative case borrows the Genitive form in both the singular and the plural. So here, the Accusative plural looks exactly like the Genitive plural.

Could kandydatów also mean a mixed group of men and women?

Yes! In Polish, if a group of people contains at least one man, we must use the masculine personal (virile) form. So ambitnych kandydatów could be a group of all men, or a mixed group of men and women.

Why is the verb zatrudnia singular if the company employs many candidates?

The verb always matches the subject. The subject here is Nasza firma (Our company), which is a single entity. Therefore, we use the third-person singular form zatrudnia (it employs), regardless of how many people the company is hiring.