A fork of Rural Dictionary
Nf, short for "nice fight," the made-in-Japan version of gg. The abbreviation is used in a positive context, similar to how you would use gg. The origin of the abbreviation is ないふぁい(Romaji: naifai), which is often seen in the chats of Japanese gaming live-streams.
In response to a good player losing a fight: Ahh, ggnf