Korean word, from the English ‘fighting’ (potentially through Japanese? Origins unknown) that is used to express encouragement or support. Used now in K-pop/Hallyu fan circles with the same meaning (so completely separate from the ‘fight’ meaning). An example of ‘reborrowing’.
Example: Good luck for the concert today! Fighting! (trans: Good luck, let’s go, you got this)
Ahn, H., & Kiaer, J. (2023). Translingual English words of Korean origin and beyond: skinship, fighting, chimaek. Asian Englishes, 26(1), 69–83. https://doi.org/10.1080/13488678.2023.2216866
Oxford Dictionary entry for ‘fighting’
Esp. in Korea and Korean contexts: expressing encouragement, incitement, or support: ‘Go on!’ ‘Go for it!’