The definition of a cynic is a person who thinks all actions are selfish and whose outlook is negative.(noun)
An example of a cynic is someone who thinks that people only volunteer so that they can receive a reward at the end.
See cynic in Webster's New World College Dictionary
Origin: L Cynicus < Gr kynikos, lit., doglike, as if < kyōn, dog (see hound), nickname of Diogenes, but prob. in allusion to the Kynosarges, a gymnasium where the Cynics taught (< kyōn + argos, lit., white dog, so named after an animal in a myth concerning Hercules, to whom the gymnasium was sacred)
See cynic in American Heritage Dictionary 4
Origin: Latin cynicus, Cynic philosopher, from Greek kunikos, from kuōn, kun-, dog; see kwon- in Indo-European roots.Word History: A cynic may be pardoned for thinking that this is a dog's life. The Greek word kunikos, from which cynic comes, was originally an adjective meaning “doglike,” from kuōn, “dog.” The word was probably applied to the Cynic philosophers because of the nickname kuōn given to Diogenes of Sinope, the prototypical Cynic. He is reported to have been seen barking in public, urinating on the leg of a table, and masturbating on the street. The first use of the word recorded in English, in a work published from 1547 to 1564, is in the plural for members of this philosophical sect. In 1596 we find the first instance of cynic meaning “faultfinder,” a sense that was to develop into our modern sense. The meaning “faultfinder” came naturally from the behavior of countless Cynics who in their pursuit of virtue pointed out the flaws in others. Such faultfinding could lead quite naturally to the belief associated with cynics of today that selfishness determines human behavior.
Learn more about cynic