Like the term tyrant, originally a respectable Ancient Greek title, and to a lesser degree autocrat, it came to be used almost exclusively as a non-titular term for oppressive, even abusive rule, yet had rare modern titular uses.
In modern usage, the term "dictator" is generally used to describe a leader who holds and/or abuses an extraordinary amount of personal power, especially the power to make laws without effective restraint by a legislative assembly. Dictatorships are often characterized by some of the following traits: suspension of elections and of civil liberties; proclamation of a state of emergency; rule by decree; repression of political opponents without abiding by rule of law procedures; these include single-party state, and cult of personality.
The term "dictator" is comparable to (but not synonymous with) the ancient concept of a tyrant, although initially "tyrant", like "dictator", did not carry negative connotations. A wide variety of leaders coming to power in a number of different kinds of regimes, such as military juntas, single-party states and civilian governments under personal rule, have been described as dictators.
In the Roman Republic the term "Dictator" did not have the negative meaning it has later assumed. Rather, a Dictator was a person given sole power (unlike the normal Roman republican practice, where rule was divided between two co-equal Consuls) for a specific limited period, in order to deal with an emergency. At the end of his term, the Dictator was supposed to hand over back to the normal Consular rule and give account of his actions - and Roman Dictators usually did.
The term started to get its modern negative meaning with Julius Caesar making himself a Dictator without a set limit to his term, and keeping the title until his assassination (which was itself largely due to Republican diehards resenting his keeping indefinite dictatorial powers).
Still, even in the 19th Century, the term "Dictator" did not always have negative connotations. For example, the Italian revolutionary Garibaldi, during his famous Expedition of the Thousand in 1860, proclaimed himself "Dictator of Sicily", which did not prevent him from being extremely popular in Italian and international public opinion. His usage of the term was clearly derived from the original Roman sense - i.e., a person taking power for a limited time in order to deal with an emergency (in this case, the need to unite Italy) and with the task done Garibaldi handed over power to the government of Victor Emmanuel II of Italy.
Garibaldi's case was, however, an exception which proved the rule. In general, the term "dictator" came to be a negative term, not a title used by rulers to call themselves but a term used by the foes of an oppressive ruler.
Mainly Latin American, Asian, and African nations, especially developing nations, have known many dictatorships, usually by military leaders at the head of a junta, either claiming to constitute a revolution or to reestablish order and stability.
In popular usage in western nations, "dictatorship" is often associated with brutality and oppression. As a result, it is often also used as a term of abuse for political opponents, for example, Henry Clay's dominance in Congress—first as Speaker of the House and later as a member of the Senate—led to his nickname, "the Dictator." The term has also come to be associated with megalomania. Many dictators create a cult of personality and have come to favor increasingly grandiloquent titles and honours for themselves. For instance, Idi Amin Dada, who had been a British army lieutenant prior to Uganda's independence from Britain in October 1962, subsequently styled himself as "His Excellency President for Life Field Marshal Al Hadji Dr. Idi Amin, VC, DSO, MC, Lord of All the Beasts of the Earth and Fishes of the Sea and Conqueror of the British Empire in Africa in General and Uganda in Particular". In "The Great Dictator" (1940), Charlie Chaplin satirized not only Hitler but the institution of dictatorship itself.
The association between the dictator and the military is a common one; many dictators take great pains to emphasize their connections with the military and often wear military uniforms. In some cases, this is perfectly legitimate; Francisco Franco was a lieutenant general in the Spanish Army before he became Chief of State of Spain; Manuel Noriega was officially commander of the Panamanian Defense Forces. In other cases, the association is mere pretense.
In Marxist ideology the dictatorship of the proletariat refers to an intermediate stage between capitalism and pure communism, where the proletariat as a class must exercise dictatorial power over the bourgeoisie. The term does not refer to power vested in a single individual, but this false interpretation has led to its use as justifying true dictatorships, such as that by individuals or a political party.
In Spanish, the word dictablanda is sometimes used for a dictatorship conserving some of the liberties and mechanisms of democracy. (The pun is that, in Spanish, dictadura is “dictatorship”, dura is “hard” and blanda is “soft”). Some examples includes Yugoslavia under Tito or Spain under Francisco Franco. This contrasts with democradura (literally “hard democracy”), characterized by full formal democracy alongside limitations on constitutional freedoms and human rights abuses, frequently within the context of a civil conflict or the existence of an insurgency. Governments in Bolivia, Chile, Colombia, Ecuador, Eritrea, El Salvador, Guatemala, Haiti, Mexico, Peru and Venezuela have at various times been considered régimes by different critics and opposition groups, not necessarily with an academic or political consensus about the application of the term emerging.
Note that these definitions disregard some alleged dictators, e.g. Benito Mussolini, who are not interested in the actual achieving of social goals, as much as in propaganda and controlling public opinion. Monarchs and military dictators are also excluded from these definitions, because their rule relies on the consent of other political powers (the barons or the army).