Integrity
Integrity was the quality of living out honesty and morality.
In 2267, Captain James T. Kirk, as a gambit to incite anger in Spock to free him from the influence of pod plant spores, described him as a traitor from a race of traitors, that a Vulcan had never lived who had an ounce of integrity. (TOS: "This Side of Paradise")
That same year, speaking honestly to Spock's mirror universe counterpart, Kirk described him as "a man of integrity in both universes". (TOS: "Mirror, Mirror")
In 2268, a Romulan commander stated that she could appreciate Vulcans as the Romulans' distant brothers, that she had heard of Vulcan integrity and personal honor and that there was a well-known saying, or possibly a myth, that Vulcans were incapable of lying. (TOS: "The Enterprise Incident")
In 2373, Lieutenant Tuvok told Marayna that he respected Ensign Harry Kim for his intelligence and integrity and assumed he held him in the same regard, but did not consider him a friend for this was an emotional dimension that Vulcans did not experience. (VOY: "Alter Ego")
That same year, when being interviewed by Doctor Lewis Zimmerman regarding the nature of Doctor Julian Bashir as part of a plan to use him as a model for the long-term Medical Holographic program, Chief Miles O'Brien described him as being an extraordinary person with a real sense of honor and integrity. (DS9: "Doctor Bashir, I Presume")