This is the act of accusing someone of hackin in a online game without solid proof.
Meaning that you have jumped to a conclusion about someone "hacking" or "cheating"
"so and so is hacking please kick them from server."
pro - "u just got owned"
nub - "thats hax, no possible way u hs me thru double doors, you hacker.
pros friend - "lol man, here we go with the haxxusations again"
p1: *snipes player 2 from across map*
p2: HAX HAX HAX
p1: Wheres your proof i was hacking
p2: YOU SHOT ME FROM ACROSS THE MAP
p1: Basic hackusation, you were standing completely still