Term used to describe someone being shutdown or shutup. Often the person has contradicted and or embarassed themselves and therefore proven the other person's point.
"You just said earlier that you prefer Coles to Aldi for nutritional value, yet now you say you like Coles better for the larger variety of chocolate candy bars based on taste preference... Rock job bro!" said Nathan to his younger, more attractive yet hairier brother Murphy.
Rockjob is a common term used in the early 1990s both for High school students and even Primary school students in Australia where the person called a Rockjob is identified as an;
1) idiot,
2) got embarrassed,
3) or usually if in an argument have made an ass of themselves