극딜 /geuk-dil/
Going all-out / Maximum damage
From gaming terminology for extreme DPS (damage per second) — putting maximum effort into attacking or criticizing something with full force.
Examples
발표에서 경쟁사 극딜했다
I went all-out attacking the competitor in the presentation
그 댓글 극딜 장난 아니다
That comment is an absolute roast — no mercy