monocracy

from WordNet (r) 3.0 (2006)

monocracy
    n 1: a form of government in which the ruler is an absolute
         dictator (not restricted by a constitution or laws or
         opposition etc.) [syn: {dictatorship}, {absolutism},
         {authoritarianism}, {Caesarism}, {despotism}, {monocracy},
         {one-man rule}, {shogunate}, {Stalinism},
         {totalitarianism}, {tyranny}]

from The Collaborative International Dictionary of English v.0.48

Monocracy \Mo*noc"ra*cy\, n. [Mono- + -cracy, as in democracy.]
   Government by a single person; undivided rule. --Sydney
   Smith.
   [1913 Webster]