Unjoin

Origin

- + un + join

Full definition of unjoin

Verb

1. (transitive) To separate or detach (things that were joined).
2. (transitive) To cease to be a member of; to leave.
• 1990, Kurt Gabel, ‎William C. Mitchell, The Making of a ParatrooperThe leader would say a pleading "Hey, fellas," instead of a commanding and enforcing "Ach-tung!" So I unjoined the Boy Scouts.