폐단이 · 폐단을
abuse, corrupt practice, evil (of a system)
Example
정부는 오래된 제도의 폐단을 없애려고 합니다.
The government is trying to eliminate the abuses of the old system.
Word parts
폐 abuse, ill+단 end, tip
Literally 'ill end' — the bad side that grows out of a practice.
Good to know
폐해 is the harm done; 폐단 is the faulty practice or system causing it.