Discommendation was a legal penalty in the Klingon Empire in which an individual was ceremonially shunned, stripped of honor, and severely reduced in social status with few rights in Klingon society. Additionally, the individual's family was shunned, as well as his descendants seven generations hence. (TNG: "Sins of the Father", "Reunion"; DS9: "The House of Quark")
The ceremony in which this punishment was meted out was simple. The Klingon about to be discommended would state, "tlhIH ghIj jIHyoj." ("I fear your judgement.") He would then be called "biHnuch" ("Coward") by the highest-ranked Klingon present, who would subsequently cross his or her arms in front of his or her chest, and turn his or her back on the recipient, while others followed suit one by one until almost all Klingons had their backs turned. The speed of this gesture varied, from formal ceremonies which were done slowly to summary punishments which could occur as quickly as the Klingons in judgment could move. (TNG: "Sins of the Father")
A discommendated Klingon became a pariah to Klingons everywhere. Other Klingons would often refuse to associate with him or her, and it was customary to refer to them as "that" (an object, rather than a person). If a Klingon did need to communicate with one who was discommendated, a specific ritual could be performed to allow it without consequences. (TNG: "Reunion")
However, dishonored Klingons did retain some basic rights, such as the right to demand vengeance for the life of a loved one. Despite being discommendated, Worf was admitted onto the IKS Vorn and was able to challenge Duras to single combat after revealing that Ambassador K'Ehleyr, whom Duras had murdered, was Worf's mate. (TNG: "Reunion")
If a Klingon leader decided to restore a discommendated Klingon's honor, he ceremonially presented his personal dagger for the Klingon to grasp by the blade tightly enough to draw blood. With this gesture, the leader stated:
- "I give you back your family honor. I give you back what was wrongfully taken from you. Let your name be spoken once again. You are ___________, son/daughter of _________________."
In 2268, Arne Darvin, an undercover operative who was discovered by James T. Kirk, was discommendated for failing to sabotage a shipment of quadrotriticale bound for Sherman's Planet. He never returned to Klingon society afterwards and eventually found himself stranded on Cardassia Prime during the Klingon-Federation War. (TOS: "The Trouble with Tribbles"; DS9: "Trials and Tribble-ations")
In 2366, Worf's father was posthumously accused of treason and Worf came to the Klingon High Council to challenge that ruling. When Worf learned that the House of Duras was actually responsible, he accepted discommendation in order to prevent the scandal from sparking a civil war. When a civil war began of its own accord, Gowron was persuaded to restore Worf's honor. (TNG: "Sins of the Father", "Redemption")
In 2371, Quark was maneuvered into marrying Grilka, whose husband, Kozak, he had unintentionally killed. After Quark learned and revealed that D'Ghor had committed a serious case of fraud, attempting to eliminate Kozak and claim his house by stealth rather than direct combat, the Klingon responded to the accusation by challenging him to a duel. Knowing that he was no match for D'Ghor in combat, Quark tried a bold stratagem. At the moment of the duel's commencement, he threw down his weapon, dropped to his knees, and freely offered his life to D'Ghor, noting that he could not prove his accusation through combat. Just before D'Ghor was about to kill Quark, Gowron intervened, and discommendated D'Ghor on the spot for the dishonor of attempted murder of an unarmed, defenseless opponent. D'Ghor was exiled and socially ruined, while Quark gained considerable admiration as an atypically courageous Ferengi. (DS9: "The House of Quark")
According to Diane Duane's novel Dark Mirror, which takes place in the mirror universe, the Klingons were conquered by the Terran Empire, who subjected the entire Klingon race to discommendation, en masse, as a way of breaking their spirit before enslaving them.
During the miniseries Star Trek: Prey, it is revealed that the most loyal followers of Kruge were sentenced with discommendation after his death on the request of the rest of Kruge's family, although this was mainly a political move as Kruge's family all sought to establish control of the house for themselves and feared Kruge's followers identifying his chosen heir. In the subsequent century, Kruge's followers set up a colony in the Briar Patch, eventually gathering other discommendated Klingons to them with the aid of Korgh, Kruge's chosen heir, hiding in the Empire under a false name. He attempts to use these Klingons – terming them "the Unsung" – as part of a complex plan to undermine the Khitomer Accords and establish the Klingon Empire as a solo power once again, but this plan is thwarted by Worf and Kahless, who help the Unsung accept that they do not have to act as though they were without honor just because of their discommendation. At the conclusion of the storyline, the remaining Unsung are cleared of their prior discommendation when Worf and Kahless argue that their ancestors were wrongfully condemned, and are then granted a chance to atone for their more recent actions by becoming the new guardians of Spirits' Forge – a spiritually important location to Klingons whose previous guardians were killed in their campaign – with Kahless accompanying them to act as a spiritual guide to help them learn what it is to be Klingon. By contrast, Korgh is subjected to discommendation for his actions against the Empire and the Federation, but his wife and children are spared this dishonor after Worf appeals to the High Council to only show discommendation to Korgh as his family were all ignorant of his true agenda.
In Star Trek Online, the House of Torg suffers discommendation by the High Council for allying with the Tal Shiar to overthrow Chancellor J'mpok and for murdering M'ven, son of Drex, heir to the House of Martok.