(Australia, slang) Ostracized and made the target of revenge or punishment.
If your number comes up you are off tap and that is that. Dead as a bloody mackerel, no questions asked. 2012, Mark Brandon Read, Chopper Unchopped:
Patty said I was placed in isolation as some members of the aboriginal community had placed me in a category known back then as "OFF TAP" meaning I was to be hurt in some way, shape or form. This would later be retracted as Ray had done one of the most stupid things one could do as an aboriginal in prison 'rape one of his own kind'. 2013, Edgar William, Defined By What I Do or Who I Am, What Makes Me Me?: