A liar, swindler, deceiver, angler was someone who was reputable for telling lies.
In 2268, the crew of the USS Enterprise was forced to once again deal with "Harry" Mudd, a con artist that they had had previous dealings with. These dealings ultimately provided an opportunity to confuse an android, Norman, who had been posing as a member of the ship's crew. Describing Mudd to Norman, James T. Kirk stated, "Everything Harry tells you is a lie. Remember that. Everything Harry tells you is a lie." Mudd then told the android, "Listen to this carefully, Norman. I am lying," trapping the android with a type of paradox and eventually leading to a breakdown due to a flood of illogic. (TOS: "I, Mudd")
In 2368, when Helena Rozhenko told Worf that his son Alexander did not always tell the truth, Worf asked if his son was a liar. She replied that he was a boy and boys sometimes took the wrong path. (TNG: "New Ground")