From dis- + unite.

• (British) IPA: /dɪsjuːˈnaɪt/

disunite (disunites, present participle disuniting; simple past and past participle disunited)

1. (transitive) To cause disagreement or alienation among or within.
   • 1863, Charles Reade, chapter 44, in Hard Cash:

     Secrets disunite a family.

2. (transitive) To separate, sever, or split.
   • 1899, Robert Barr, chapter 16, in Jennie Baxter, Journalist:

     I have discovered how to disunite that force and that particle.

3. (intransitive) To disintegrate; to come apart.
   • 1843, Robert Browning, A Blot In The 'Scutcheon, act I:

     You cannot bind me more to you, my lord.
     Farewell till we renew... I trust, renew
     A converse ne'er to disunite again.

• disunity