DictionarysecedeFormal withdrawal
verb

secede

sih-SEED/sɪˈsiːd/

To formally withdraw from a political union or organization.

The province threatens to secede from the union over new taxes.

A two-stage diplomatic scene shows a member state formally leaving an alliance: its delegate voluntarily removes his national flag from the shared council display while presenting a sealed withdrawal document, then stands with that flag apart from the continuing council.
Etymology

To secede is literally to “go apart.” The earlier meaning of leaving one’s companions or withdrawing became the more specific act of withdrawing from a political or religious union.

In context

The People Profiles31:19
Others were willing to secede from the union over their views. On the 20th of December 1860 South Carolina led the way and became the first state to declare independence from the United States.
John Wilkes Booth - Why He Killed Lincoln

More examples

  • The local chapter seceded from the national organization after a dispute.
  • Voters reject a proposal to secede and form an independent country.
  • The constitution prevents member states from seceding without approval.

Forms

secede · secedes · seceded · seceding

secession noun — Formal withdrawal from a union or organization.

secessionist noun — Someone who supports withdrawal from a union.

Similar words

withdraw
Withdraw is broader and need not involve formal political separation.
separate
Separate emphasizes becoming distinct, not necessarily leaving an established union.