1. What does it mean?
항마력 evokes resistance to demonic forces in fantasy settings. Online, that defensive power becomes the capacity to sit through cheesy dialogue, exaggerated affection, or an awkward performance without looking away.
Also written or said as hangmaryeok
2. The nuance
Saying 항마력이 부족하다 means the scene is too cringey for you, not that it is objectively bad. It can sound dismissive when aimed at someone's sincere expression of affection.
3. Examples
“직접 쓴 고백 대사를 읽으려니 항마력이 필요하네.”
Reading out the confession line I wrote is taking some serious cringe resistance.
“어릴 때 찍은 연극 영상은 항마력 없으면 못 봐.”
I can't watch my childhood play video without a high tolerance for embarrassment.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.