- "Lies! All lies! You are the greatest liar I have ever met!"
- - Garth of Izar
A lie is a deliberate statement which is untrue, usually as a means to deceive or mislead another individual. Someone who told a lie is called a "liar".
One of the great myths surrounding Vulcans was that the race was incapable of telling a lie. While generally believed to be accurate, Vulcans were in fact capable of telling lies, usually justifying this action as a logical course towards a means to an end. An example of this would be lying to carry out a secret mission or lying to protect the lives of others. Both Spock and Valeris were capable of lying, although Valeris' motives were somewhat dubious. Tuvok admitted that the notion Vulcans could not lie was a myth and that he had not found a logical need to lie, after an inquiry by Seven of Nine into whether or not they were capable of lying. (TOS: "The Enterprise Incident"; Star Trek VI: The Undiscovered Country; VOY: "Hunters")
Miranda Jones once called James T. Kirk a liar, proclaiming, "It's a lie!" when Kirk stated that Jones had tried to murder Spock while mind melding with a Medeusan. (TOS: "Is There in Truth No Beauty?")
Data once told Timothy that androids do not lie; however, Data himself was very capable of lying. Data once lied to the entire crew of the USS Enterprise-D, regarding an incident wherein the Paxans erased the memories of the Enterprise's crew (except for Data) due to a xenophobic fear bordering on the extreme. Data also once lied to an entire bar full of patrons in an effort to make Ro Laren appear as a Maquis sympathizer, as part of an elaborate plan to infiltrate a local resistance cell. In both of these cases, however, Data was acting under direct orders and not by his own design. Data also lied to Samuel Clemens about the purpose of a machine he was building when displaced in time, most likely in accordance with Starfleet's temporal displacement policy. (TNG: "Hero Worship", "Clues", "Preemptive Strike", "Time's Arrow, Part II") Data's brother, Lore, also possessed the capability to lie and lied to Data about which of them had been constructed first. (TNG: "Datalore")
When Elim Garak was in danger of dying due to a malfunctioning cranial implant, he told Doctor Julian Bashir a number of conflicting stories regarding his past. After the danger had passed, Bashir asked of him which of the stories were true and which weren't. Garak replied that they all were true and Bashir asked "Even the lies?", to which Garak responded "Especially the lies." (DS9: "The Wire")
When the Romulan Ruwon was interrogating Quark, he told him he thought he was lying. Quark asked about which part and Ruwon replied "All of it," to which Quark responded that he was at least consistent. (DS9: "Visionary")
In 2373, when Elim Garak decoded a secret Cardassian transmission, a Changeling posing as Doctor Julian Bashir caught him in a lie that it was a five-year-old planetary survey report. When Garak then suggested that they steal a runabout to search for Enabran Tain, "Bashir" replied "You want me to lie to my commanding officer, violate Starfleet regulations, and go with you on a mission into the Gamma Quadrant which will probably get us both killed?" Later, when Garak went on said mission with Lieutenant commander Worf, he spun a story about wanting to attend Starfleet Academy. When Worf realized that Garak really had no desire to attend Starfleet Academy, he asked Garak what the reason was for all the deception, and Garak replied that "lying is a skill like any other, and if you want to maintain a level of excellence, you have to practice constantly." Worf told him to practice on someone else. (DS9: "In Purgatory's Shadow")
In 2374, Captain Benjamin Sisko concocted an elaborate plan to draw the Romulan Star Empire into the Dominion War. Although the plan was approved by Starfleet Command, Sisko commented in a later deleted personal log that "I was the one who had to look Senator Vreenak in his eye and convince him that a lie was the truth." (DS9: "In the Pale Moonlight")