The Collaborative International Dictionary of English v.0.48:

Deposal \De*pos"al\, n.
   The act of deposing from office; a removal from the throne.
   --Fox.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

61 Moby Thesaurus words for "deposal":
   abdication, cashiering, conge, deconsecration, defrocking,
   demission, deposition, deprivation, dethronement, disbarment,
   disbarring, discharge, discrownment, disemployment,
   disenthronement, dislodgment, dismissal, displacement, displacing,
   drumming out, emeritus status, excommunication, expulsion, firing,
   forced resignation, forced separation, furloughing, impeachment,
   kicking upstairs, layoff, liquidation, ousting, overthrow,
   overthrowal, pensioning off, pink slip, purge, relinquishment,
   removal, resignation, retiral, retirement, superannuation,
   surplusing, suspension, the ax, the boot, the bounce, the gate,
   the sack, ticket, unchurching, unfrocking, unhorsing, unplacement,
   unsaddling, unseating, upset, voluntary resignation,
   walking papers, withdrawal