This is the 943rd most frequent Polish word.
partnera
"Partnera" means "partner" (genitive or accusative singular form) in English.
Here, 'partnera' refers to a collaborative or romantic partner, used in the accusative case as it is the object of the verb 'poproś' (ask).
Poproś swojego partnera o pomoc w zadaniu.
Ask your partner for help with the task.
In this sentence, 'partnera' indicates a dancing partner and is in the genitive case due to the negative context of the verb 'znalazłem' (I found).
Nie znalazłem jeszcze odpowiedniego partnera do tańca.
I haven't yet found a suitable partner for dancing.
Here, 'partnera' denotes a romantic partner and is in the accusative case as it is the object of the action 'zaprosiła' (invited).