cynic

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A person who believes all people are motivated by selfishness.
2. n. A person whose outlook is scornfully and often habitually negative.
3. n. A member of a sect of ancient Greek philosophers who believed virtue to be the only good and self-control to be the only means of achieving virtue.
4. adj. Cynical.
5. adj. Of or relating to the Cynics or their beliefs.

Century Dictionary and Cyclopedia

1. Of or pertaining to a dog; dog-like: as, cynic spasm.
2. Of or pertaining to the dog-star: as, the cynic year.
3. Belonging to the sect of philosophers called Cynics; resembling the doctrines of the Cynics.
4. Having the character or qualities of a cynic; cynical.
5. n. [capitalized] One of a sect of Greek philosophers founded by Antisthenes of Athens (born about 444 b. c.), who sought to develop the ethical teachings of Socrates, whose pupil he was. The chief doctrines of the Cynics were that virtue is the only good, that the essence of virtue is self-control, and that pleasure is an evil if sought for its own sake. They were accordingly characterized by an ostentatious contempt of riches, arts, science, and amusements. The most famous Cynic was Diogenes of Sinope, a pupil of Antisthenes, who carried the doctrines of the school to an extreme and ridiculous asceticism, and is improbably said to have slept in a tub which he carried about with him.
6. n. A person of a cynical temper; a sneering faultfinder.

Wiktionary

1. n. A person who believes that all people are motivated by selfishness.
2. n. A person whose outlook is scornfully negative.

GNU Webster's 1913

1. adj. Having the qualities of a surly dog; snarling; captious; currish.
2. adj. Pertaining to the Dog Star.
3. adj. Belonging to the sect of philosophers called cynics; having the qualities of a cynic; pertaining to, or resembling, the doctrines of the cynics.
4. adj. Given to sneering at rectitude and the conduct of life by moral principles; believing the worst of human nature and motives; disbelieving in the reality of any human purposes which are not suggested or directed by self-interest or self-indulgence; having a sneering disbelief in the selflessness of others; ; characterized by such opinions.
5. n. One of a sect or school of philosophers founded by Antisthenes, and of whom Diogenes was a disciple. The first Cynics were noted for austere lives and their scorn for social customs and current philosophical opinions. Hence the term Cynic symbolized, in the popular judgment, moroseness, and contempt for the views of others.
6. n. One who holds views resembling those of the Cynics; a snarler; a misanthrope; particularly, a person who believes that human conduct is directed, either consciously or unconsciously, wholly by self-interest or self-indulgence, and that appearances to the contrary are superficial and untrustworthy.

WordNet 3.0

1. n. a member of a group of ancient Greek philosophers who advocated the doctrine that virtue is the only good and that the essence of virtue is self-control
2. n. someone who is critical of the motives of others