Definition
To either improve one's behavior or else be required to leave; to either improve one's performance in an activity or else withdraw from that activity completely.
In Context
- "Portions of those letters quoted by Bruccoli indicate that though Hemingway could be sympathetic, he used a lot of ink telling Fitzgerald to shape up or ship out."
See Also
- shit or get off the pot
- fit in or fuck off
- up or out