There are actually two different paths to follow when searching for the meaning of cynicism. To the ancient Greeks, Cynicism (capitalized) was a school of philosophy and social criticism founded by a man named Antisthenes. Followers of Cynicism often rejected the material comforts and social practices of the world around them, preferring to live as simply and as virtuously as possible. Because these Cynics often refused to bathe and were frequently found shouting incoherently in public areas, they were called kuon, the Greek word for dogs. Therefore, these men became known historically as the "dog philosophers".
Perhaps the best known follower of the Greek Cynicism movement was a man named Diogenes. Legend has it that Diogenes wandered the Greek countryside, allegedly on a never ending quest for an honest man. Honesty and virtue were key elements of the original Cynicism philosophy. The problem was that in the Cynics' eyes, few Greek politicians or prominent members of the ruling class had either of those qualities. Society in general was ruled by thoughts of personal gain, political corruption and meaningless rituals.
In the modern sense of the word, cynicism is a personal belief that people are motivated primarily by their own self-interests, and the natural order of things leans towards disintegration and corruption. Those who embrace cynicism often separate themselves from the rest of society, believing that society-at-large has largely abandoned its core value system. Politicians only take action when there is personal gain, and the corporate world is primarily motivated by greed and corruption. From the viewpoint of cynicism, these circumstances will not improve because the people capable of making these changes are stymied by apathy and fear.
A modern cynic may see himself as a social critic, whose negative opinions do serve a valid purpose. Cynicism is not without its constructive aspects, since political and social leaders do need to understand the negative aspects of their intentions or actions. But those who embrace the most extreme elements of cynicism run the risk of losing their credibility as "devil's advocates." When cynicism is coupled with feelings of bitterness or resignation, a modern cynic could find himself completely isolated from the world around him, including family and friends who can no longer cope with the conspiratorial thoughts and unrelenting negativity associated with extreme cynicism.