Definition
This idiom is used to warn someone that they must improve their performance or behavior, or they will be required to leave.
The manager told the staff, 'Shape up or ship out! You need to improve your work efficiency, or you’ll have to leave!'
‘I’m not going to tolerate your excuses anymore, shape up or ship out!’ the supervisor said sternly.
The company made it clear: 'If sales numbers don't increase, some people will have to shape up or ship out.'