A character steadfastly sticks to a traditional moral code in spite of temptation to do otherwise. It nearly always has to do with being honest and defending ones reputation. It very often involves Klingons.

Examples:
Worf, being a true man of honor, implored the Klingon authorities to grant honorable deaths to three Klingon renegades whom he had come to respect in tng1x20 "Heart of Glory".

References:
https://en.wikipedia.org/wiki/Honour