It's a combination of "grub" and "rubbish", making another word for junk food.
I don't feel like cooking tonight. Let's just go out and pick up some grubbish.
af luckysocks113 6. august 2014
A mix of garbage and rubbish, usually in the context of source-code.
Fix that routine- it's absolute grubbish.
af Rev. Five 25. maj 2005