cynic
Pronunciation: /ˈsɪnɪk/
noun
- 1a person who believes that people are motivated purely by self-interest rather than acting for honourable or unselfish reasons: some cynics thought that the controversy was all a publicity stunt
- a person who questions whether something will happen or whether it is worthwhile: the cynics were silenced when the factory opened

Origin:
mid 16th century (in cynic (sense 2)): from Latin cynicus, from Greek kunikos; probably originally from Kunosarges, the name of a gymnasium where Antisthenes taught, but popularly taken to mean 'doglike, churlish', kuōn, kun-, 'dog' becoming a nickname for a Cynic