This is the 4674th most frequent Polish word.
najgorszy
Worst.
Here, 'najgorszy' is used as an adjective to describe the intensity of the noun 'dzień' (day), referring to the most negative or undesirable possibility.
To był najgorszy dzień w moim życiu.
This was the worst day of my life.
In this sentence, 'najgorszym' demonstrates its usage in the instrumental case, modifying 'uczniem' (student), to denote the least favorable or skilled individual.
On jest najgorszym uczniem w klasie.
He is the worst student in the class.
In this case, 'najgorsza' qualifies 'decyzja' (decision) in the nominative case, aiding in expressing the quality of being the least wise or preferable option.