This is quite an old phrase, dating back to WW2 at least. To "get a rocket" is to be scolded or told off, usually by someone in authority; boss, manager, teacher, parent, etc. It may go as far as dismissal.
I think Nigel made another mistake. He's going to get a rocket for that!
by New Old School January 02, 2012
Can you define these popular missing words?