This is the 12020th most frequent Polish word.
lekarzem
"lekarzem" — "a doctor" (instrumental case in Polish).
In this sentence, 'lekarzem' is used as an instrumental case form for the noun 'lekarz' (doctor), describing the role or profession someone aspires to acquire.
Moim marzeniem zawsze było zostać lekarzem.
My dream has always been to become a doctor.
This usage of 'lekarzem' showcases its function within the instrumental case, denoting the profession one participates in.
Pracował jako lekarzem przez wiele lat.
He worked as a doctor for many years.
Here, 'lekarzem' is also in the instrumental case, used after the verb 'rozmawiać' (to talk/speak) to indicate the person with whom the conversation is held.