1. What does it mean?
극딜 combines extreme with 딜, damage. In games it means focusing heavy damage into a target or short window. Outside games it can describe someone receiving a barrage of harsh criticism or teasing.
Also written or said as geukdil
2. The nuance
A gaming instruction to 극딜 is about damage output, not necessarily cruelty. When applied to people, it can describe hurtful piling-on, so tone and consent matter.
3. Examples
“보스가 멈췄을 때 극딜을 넣었어.”
We unleashed our biggest burst of damage while the boss was stationary.
“실수 하나로 극딜하지 말고 해결책을 얘기하자.”
Let's discuss a solution instead of piling on over one mistake.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.