"to send home (troops) as not required for active service," 1876, probably a back-formation from demobilization (q.v.). Related: Demobilized; demobilizing.
Entries linking to demobilize
demobilization n.
"action of disbanding troops; reduction of military forces to a peace status," 1866 (in reference to the Austro-Prussian War); see de- (privative) + mobilization. Earlier in German.
demob v.
1919, short for demobilize. Originally in reference to troops returning to civilian life at the end of World War I. Related: Demobbed.