shape up or ship out

shape up or ship out

To either improve behavior, performance, or attitude, or else (be forced to) leave (a job, relationship, living situation, etc.). I've warned you about turning up to work late for the last time—you need to shape up or ship out! Jen got so fed up with her girlfriend's drinking that she told her to shape up or ship out.
See also: out, shape, ship, up
Farlex Dictionary of Idioms.

Shape up or ship out.

Fig. Either improve one's performance (or behavior) or leave. (Used as a command.) Okay, Tom. That's the end. Shape up or ship out! John was late again, so I told him to shape up or ship out.
See also: out, shape, ship, up
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

shape up or ship out

INFORMAL
If you tell someone to shape up or ship out, you are telling them that they should improve their behaviour or performance, or else leave. Coach Kevin Wall has warned his players to shape up or ship out.
See also: out, shape, ship, up
Collins COBUILD Idioms Dictionary, 3rd ed.

shape up or ship out

used as an ultimatum to someone to improve their performance or behaviour or face being made to leave. informal, chiefly North American
See also: out, shape, ship, up
Farlex Partner Idioms Dictionary

ˈshape up or ship ˈout

(American English, informal) used to tell somebody that if they do not improve, work harder, etc. they will have to leave their job, position, etc: Two players have been told by the manager to shape up or ship out.
See also: out, shape, ship, up
Farlex Partner Idioms Dictionary

shape up or ship out

in. improve or get out. I’ll tell you one more time. Shape up or ship out!
See also: out, shape, ship, up
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

shape up or ship out

Behave yourself or leave. This term originated in the American armed forces during World War II, when it literally meant, behave like a soldier (sailor, marine) or be sent overseas to a combat zone. After the war the saying was extended to any situation calling for improved performance, as, for example, a warning to an employee to do better or be fired.
See also: out, shape, ship, up
The Dictionary of Clichés by Christine Ammer
See also:
  • devil-may-care attitude
  • cop an attitude
  • change one's tune, to
  • sing a different song
  • sing a different song/tune
  • sing a different tune
  • sing another tune
  • have a bad attitude
  • put (one) right
  • put someone right