This is the 12030th most frequent Polish word.
lepsi
"Lepsi" means "better" (plural form) in English.
'Lepsi' is used here as a comparative adjective to describe the students' superior skill level in mathematics.
Ci studenci są lepsi w matematyce.
These students are better at mathematics.
Here, 'lepsi' is used in a different form as 'lepsza' to compare the quality of two events.
Impreza w parku była lepsza niż ta w zeszłym tygodniu.
The party in the park was better than the one last week.
In this sentence, 'lepsi' is used metaphorically, suggesting improvement in behavior towards one another.