Definitions of break up
to end a business or other relationship, especially because those involved no longer like each other or not longer want to be together to work together
If things carry on like this, I'm sure they'll break up.
to separate something into into smaller pieces, especially gradually
Will Scotland ever vote to break up the United Kingdom?
to stop something from continuing
Police deployed pepper spray to break up an altercation between two female students at Park High School.