The Oxford English Dictionary traces the word to the Spanish word hombredad, meaning manliness, modified after the Sicilian word omu "man". According to a different theory, the word comes from Latin humilitas, which became umirtà and then finally omertà in some southern Italian dialects. The first Antimafia Commission of the Italian parliament in the 1970s accepted the origin based on omu on the authority of Antonio Cutrera, with no reference to Spanish. The basic principle of omertà is that it is not "manly" to seek aid from legally constituted authorities to settle personal grievances. The suspicion of being a cascittuni constitutes the blackest mark against manhood, according to Cutrera. An individual who has been wronged is obligated to look out for his own interests by avenging that wrong himself or finding a patron but not the state to do the job. Omertà implies "the categorical prohibition of cooperation with state authorities or reliance on its services, even when one has been victim of a crime." A person should absolutely avoid interfering in the business of others and should not inform the authorities of a crime under any circumstances, but if it is justified, he may personally avenge a physical attack on himself or on his family by vendetta, literally a taking of revenge, a feud. Even if somebody is convicted of a crime that he has not committed, he is supposed to serve the sentence without giving the police any information about the real criminal, even if the criminal has nothing to do with the Mafia. Within Mafia culture, breaking omertà is punishable by death. Omertà is an extreme form of loyalty and solidarity in the face of authority. One of its absolute tenets is that it is deeply demeaning and shameful to betray even one's deadliest enemy to the authorities. For that reason, many Mafia-related crimes go unsolved. Observers of the Mafia debate whether omertà should best be understood as an expression of social consensus for the Mafia or whether it is instead a pragmatic response based primarily on fear, as implied by a popular Sicilian proverbCu è surdu, orbu e taci, campa cent'anni 'mpaci. It has also been described as follows: "Whoever appeals to the law against his fellow man is either a fool or a coward. Whoever cannot take care of himself without police protection is both. It is as cowardly to betray an offender to justice, even though his offences be against yourself, as it is not to avenge an injury by violence. It is dastardly and contemptible in a wounded man to betray the name of his assailant, because if he recovers, he must naturally expect to take vengeance himself."
History
Omertà is a code of silence, according to one of the first Mafia researchers Antonio Cutrera, a former officer of public security. It seals lips of men even in their own defense and even when the accused is innocent of charged crimes. Cutrera quoted a native saying which was first uttered by a wounded man to his assailant: "If I live, I'll kill you. If I die, I forgive you." Sicilians adopted the code long before the emergence of Cosa Nostra, and it may have been heavily influenced by centuries of state oppression and foreign colonisation. It has been observed at least as far back as the 16th century as a way of opposing Spanish rule. The Italian-American mafioso Joe Valachi famously broke the omertà code in 1963, when he publicly spoke out about the existence of the Mafia and testified before a US Senate committee. He became the first in the modern history of the Italian-American Mafia to break his blood oath. In Sicily, the phenomenon of pentito broke omertà. Among the most famous Mafia pentiti is Tommaso Buscetta, the first important witness in Italy, who both helped prosecutor Giovanni Falcone to understand the inner workings of Cosa Nostra and described the Sicilian Mafia Commission or Cupola, the leadership of the Sicilian Mafia. A predecessor, Leonardo Vitale, who gave himself up to the police in 1973, was judged mentally ill and so his testimony led to the conviction of only himself and his uncle.
In sport
Omertà is widely reported in sport in relation to use of prohibited substances by athletes. The Cycling Independent Reform Commission report of 2015 contains the word "omerta" no fewer than 17 times, and stated:
wrote novels based on the principles of Omertà and the Cosa Nostra. His best known works in that vein are the trilogy The Godfather, The Sicilian, and Omertà. The final book of the series, Omertà, was finished before his death but published posthumously in 2000 from his manuscript.