Despot
Despot , noun
[French despote, Late Latin despotus, from Greek despo`ths master, lord, the second part of which is akin to po`sis husband, and Latin potens. See Potent.]
1.
A master; a lord; especially, an absolute or irresponsible ruler or sovereign.
Irresponsible power in human hands so naturally leads to it, that cruelty has become associated with despot and tyrant.
2.
One who rules regardless of a constitution or laws; a tyrant.