This is the 15898th most frequent Polish word.
tenisistek
"Tenisistek" means "female tennis players" in English.
In this sentence, 'tenisistek' is the genitive plural form of 'tenisistka', indicating possession ('the game of the best female tennis players').
Śledziłam grę najlepszych tenisistek na turnieju.
I followed the game of the best female tennis players at the tournament.
Here, 'tenisistek' is in the genitive plural form, showing 'for beginner female tennis players' in a context indicating something provided to them.
Klub organizuje specjalne treningi dla początkujących tenisistek.
The club organizes special training sessions for beginner female tennis players.
The word 'tenisistek' in this sentence is used in a genitive plural form, expressing 'among the female tennis players', indicating the group being referred to.