The *original* definition of this word dates back to 1986 in Rancho Cordova, CA. It was co-created by two schoolmates to define a certain "je ne sais quoi" quality that a person may have which gives them extremely good luck or extremely bad luck in any certain situation. As it's unquantifiable and impossible to predict the outcome thereof as a characteristic trait one has, it's simply known as "the extreme luck of the good or the bad".
The term jivvy eventually found its way into multiple role-playing games created by these two individuals, Greg S. and Jeremie L., whereas it defined a chaotic character trait much in the same way one would use "stamina", "hit points", or "agility" in a role-play type game. It was a trait rolled upon and used in similar fashion.
"By sheer jivvy, tripping off the 10 storey roof left behind him a chain-reactive series of events which carried themselves into the building and down with lightning quickness, such that when his body was to meet the pavement, the chain-reaction ended ultimately in the happenstance of causing a grossly over-inflated twenty-person liferaft to skid out of the building's front doors and appear in the pavement's place, which predictably had the fortunate affect of saving his life by stopping his fall outright."
"The jivvy isn't with you today." "Why do you say that?" "You just rolled snake-eyes fifty times in a row, dropped $5000 on Don't Pass, and then rolled a Hard Six. It's more like jivvy REALLY hates you right now.