This is the 16288th most frequent Polish word.
uszami
"Uszami" in Polish means "with ears" or "using ears."
"Uszami" is again in the instrumental case, describing how the bunny was moving its ears.
Zajączek ruszał uszami.
The bunny was moving its ears.
Instrumental case is used to indicate the means or tool of the action, here "uszami" (ears) as the tool of hearing.
Słyszałem to uszami.
I heard it with my ears.
Used metaphorically, "uszami" refers to imagining hearing or perceiving through imagination, providing a figurative element to the sentence.