Cynic

–noun
1. a person who believes that only selfishness motivates human actions and who disbelieves in or minimizes selfless acts or disinterested points of view.
2. (initial capital letter ) one of a sect of Greek philosophers, 4th century b.c., who advocated the doctrines that virtue is the only good, that the essence of virtue is self-control, and that surrender to any external influence is beneath human dignity.
3. a person who shows or expresses a bitterly or sneeringly cynical attitude.

–adjective
4. cynical.
5. ( initial capital letter ) Also, Cynical. of or pertaining to the Cynics or their doctrines.
6. Medicine/Medical Now Rare . resembling the actions of a snarling dog.



Use cynic in a Sentence: Niccolo Machiavelli was a cynic of contemporary Italian politics. 


Origin:
1540–50; < L Cynicus < Gk Kynikós Cynic, lit., doglike, currish, equiv. to kyn- (s. of kýōn ) dog + -ikos - ic

—Related forms
an·ti·cyn·ic, noun, adjective

—Can be confused:  cynic, optimist, pessimist, skeptic.

—Synonyms
1, 3. skeptic, pessimist, misanthrope.


Source:
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2010.