Goof

May be used as an abbreviation for “Get Out Or Fight”.

Prison dude: “Get lost goof!”
You: “F*ck you, fight me b*itch!”

JNS

In snowboarding usually, like big air or in the Olympics, means “Jump Not Scored”.

The snowboarder fell when trying to land his jump, ‘JNS’ appeared on the score board.

luminisk

Is a word that may be said when you’re laughing and are incomprehensible.
Can also be heard when someone doesn’t hear what you said and just decides you’re weird and thinks you just like saying funny things.

You: “Hey dude, look at Vik, he’s being so weird haha”.
Dude: “Heheheh... luminisk...”.