This is the 6364th most frequent Polish word.
buenos
The word "buenos" is not Polish; it is Spanish and means "good" in English (plural form, masculine or mixed gender).
Used as a greeting in a mixed Polish-Spanish context to say 'good morning' (buenos días).
Buenos días, jak się dziś czujesz?
Good morning, how are you feeling today?
'Buenos' appears adjectively describing 'articles,' but note it might not be standard in Polish; it reflects a loan word usage.
Marek przeczytał kilka artykułów buenos.
Marek read a few good articles.
This explains the colloquial use of 'buenos' as an abbreviation.