The definition of honor varied widely between cultures, as did the importance placed upon it. Honor was normally synonymous with dignity and referred to the upholding of one's values. The Klingons were notorious for the emphasis they placed on honor.
This may have been a more abstract way of viewing honor. But, as notions of honor were often very subjective, putting emphasis on clear objects (i.e. victory) made the Klingon able to deduce the honorable conduct (i.e. meanings used to achieve victory).
Honor was one of the most important components of Klingon philosophy. However, it was significantly different from most other cultures' definition of the word. For example, Worf once said that "Nothing is more honorable than victory". From this point of view, using a cloaked ship to ambush enemies could be considered honorable if it achieved victory. (DS9: "The Way of the Warrior")
The notion of honor seemed to be highly relative and open to debate. Each and every Klingon could possibly have his own interpretation of what consisted of an honorable means to achieve an end. Even more, some decisions were paradoxical because two different view of honor were in contradiction. For instance, Worf indicated that it was necessary to challenge Gowron's leadership (for he's presumably acting in a dishonorable way) while General Martok was convinced that it was dishonorable to challenge the leader of the Empire in the middle of a war. In another case, while Dr. Antaak's deception in claiming to have stabilized Augment DNA, allowing the creation of Klingon Augments, when he and Phlox had merely cured the augment virus might be seen by some as dishonorable, Antaak himself believed that, given the millions of lives this cure would save, his near-certain execution if caught would be as honorable a death as a doctor could have. (DS9: "Tacking Into the Wind", ENT: "Divergence")
Hence, dishonor is sometimes a concept which compels Klingons to action.