cynic
nounUK /ˈsɪnɪk/
US /ˈsɪnɪk/
A cynic is someone who thinks people only do things for themselves and never really care about others.
My uncle is such a cynic that he doesn't believe anyone ever gives money to charity without wanting something back.
OTHER MEANINGS
2. A member of an ancient Greek school of philosophy that taught people to live simply and not care about money or fame.
The ancient Cynic Diogenes famously lived in a barrel and owned almost nothing.
3. A person who believes that people are only motivated by selfish reasons.
As a cynic, she assumed the surprise party was just an excuse to get free food.
4. Showing a distrustful or mocking attitude toward other people's honesty or kindness.
His cynical remark about the donation made everyone in the room uncomfortable.