Wiktionary
rack off
vb. 1 (&lit rack off English) 2 (context Australia informal English) To go away; to sod off.
Usage examples of "rack off".
Then she ambled toward the hillock where Firbek wrestled the rocket launching rack off the cart.
They go over to the table and Maledicta grabs a rack off the wall.
One of the children waiting to have a book bought for him knocked a plastic letter-rack off a shelf and broke it, and got smacked by his mother and dragged out while nearly everyone turned to watch.