This is the 12658th most frequent Polish word.
niechlubnego
"Niechlubnego" means "disgraceful" or "dishonorable" in English.
In this sentence, 'niechlubnego' is used as an adjective describing 'wystąpienia,' meaning 'speech,' and conveys the negative connotation associated with it.
Jego niechlubnego wystąpienia długo nie zapomnimy.
We won't forget his infamous speech for a long time.
Here, 'niechlubnych' is in the plural form and denotes negative historical events, illustrating its use in discussions about past occurrences.
Historia zawiera wiele niechlubnych momentów pełnych konflików i wojen.
History contains many infamous moments full of conflicts and wars.
In this instance, 'niechlubnego' modifies 'postępku,' indicating the negative moral judgment of the action.