From Longman Dictionary of Contemporary Englishbreakaway group/party/movementbreakaway group/party/movementLEAVE A JOB OR ORGANIZATIONa breakaway group etc is formed by people who have left another group because of a disagreement a breakaway group of journalists Hundreds of miners joined the breakaway union. → break away at break1 → breakaway
Examples from the Corpus
breakaway group/party/movement• Nor were there frustrated breakaway movements from a handful of top clubs.• Thus the breakaway group, organizing its own exhibition, was an obvious initiative.• Members of a breakaway group who blocked traffic in University Square the same evening were forcibly dispersed by police.• De Rossa said that his breakaway group would form a new democratic socialist party. 