He abused his position to engage in fraud for personal gain.
Tips
usage
弊 typically appears in compound words: 利弊 (pros and cons), 舞弊 (fraud), 作弊 (to cheat). As a standalone character it has a classical feel and is more common in written or formal Chinese.
memory
Think of 弊 as covering something up (廾 hands at the bottom, 敝 meaning worn-out on top) — something worn and hidden, like a fraud.
Bottom shows two hands held up — the indexing radical. Added to 敝 it suggests hands lifting up or presenting the defect; some readings interpret it as 'holding aloft the worn-out cloth'. In modern use 弊 names disadvantage, fraud, the bad side of something — 利弊 'pros and cons'.
Top supplies the sound and most of the meaning: bì → bì (exact match). 敝 originally pictured a cloth being beaten ragged — 'worn out, defective, broken-down'. From that, 弊 inherited the sense of defect, harm, malpractice, the rot inside a system.