The word "Bare" as in lots or many, and the word "Hax" as in tampering with something. Like when a computer hacker illegally obtains data (information) from a computer.
So a bare hax would be someone that you think is cheating in a computer game. Its even possible that they aren’t cheating but they are just better than you. And instead of accepting it, you proclaim that they are cheating, by saying “bare hax”