This is the 485th most frequent Polish word.
trenera
The Polish word "trenera" means "coach" or "trainer" (genitive or accusative singular form of "trener").
Here, 'trenerem' (the instrumental case of 'trener') refers to a person who is a fitness instructor, demonstrating its use to denote a title or role.
Spotkałem się wczoraj z moim trenerem fitness.
I met with my fitness trainer yesterday.
Here, 'trenera' (accusative case of 'trener') is used to refer to a person in a direct action or feeling, illustrating its grammatical usage as the object of admiration.
Podziwiam determinację mojego trenera.
I admire my coach's determination.
In this context, 'trenera' (genitive case of 'trener') indicates possession or relation, showing its use to describe the important attributes of the coach.