1. What does it mean?
막타 means the last strike. In games it is the hit that defeats an enemy or secures an objective, sometimes determining who receives credit or a reward. Outside games it can jokingly mean the final remark that settles something.
Also written or said as makta
2. The nuance
Getting the final hit is not the same as doing all the work. Reward rules vary by game, and 막타 is not automatically an accusation of stealing credit.
3. Examples
“체력을 보고 막타 타이밍을 맞췄어.”
I watched the health bar and timed the finishing hit.
“보스 막타는 친구가 넣었지만 다 같이 잡은 거야.”
My friend landed the boss's final hit, but we defeated it together.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.