This is the 5693rd most frequent Polish word.
wybranym
"Chosen" or "selected" (instrumental or dative singular form).
The word 'wybranym' is used as an adjective to describe individuals who have been selected.
Ten prezent został wręczony wybranym osobom.
This gift was given to selected individuals.
Here, 'wybranym' functions as a noun representing a group of selected individuals.
Wybranym przysługuje specjalne traktowanie.
The chosen deserve special treatment.
In this sentence, 'wybranego' (inflected form of 'wybranym') describes the teacher as the one I have chosen.