정학이 · 정학을
suspension (from school)
Example
그 학생은 폭력 사건으로 정학을 당했어요.
That student was suspended over a violent incident.
Word parts
정 stop+학 study
Literally 'stopping study'.
Good to know
Don't confuse it with 휴학: 정학 is a punishment, while 휴학 is a leave you choose.