This is the 6054th most frequent Korean word.
선생의
"Of the teacher" or "teacher's."
In this case, '선생의' identifies qualities (자질) belonging or pertaining to the teacher (선생).
선생의 자질은 매우 중요합니다.
A teacher's qualities are very important.
In this sentence, '선생의' conveys possession, associating teaching (가르침) directly to the teacher (선생).
선생의 가르침은 많은 제자들에게 영감을 주었습니다.
The teacher's teaching inspired many students.
Here, '선생의' again indicates possession, connecting guidance (지도) to the teacher (선생).