1. What does it mean?
갑질 refers to high-handed treatment by a person or organization in a stronger position, such as making unreasonable demands or humiliating someone dependent on them. 갑 evokes the dominant party in a 갑–을 relationship.
Also written or said as gapjil
2. The nuance
It is a critical social term, not a finding about a particular legal offense. Describe the behavior clearly rather than treating every disagreement with a senior person as abuse.
3. Examples
“직급을 앞세워 모욕하는 건 갑질이라는 비판을 받았어.”
Using rank to humiliate people drew criticism as an abuse of power.
“정당한 요청과 갑질은 구분해서 얘기해야 해.”
We should distinguish a reasonable request from an abuse of authority.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.