Funny, I looked it up do see its exact definition. Basically, it means, you think everyone is acting in their own self-interest, and that no one acts for the good of others . . . unless they're going to get something out of it too. So, if someone seems to be being nice to you, you suspect that they are doing it for some hidden reason - - maybe they want you to do something for them. A cynical person would tend not to believe in heroes, saints, etc.

I don’t believe any politician ever does things to help us, but only to help themselves. I’m full of cynicism today!

Cynicism is the belief that people are motivated purely by self-interest rather than by genuine kindness or integrity. Cynics tend to be skeptical, distrustful, and sometimes sarcastic about human nature and society. Example sentence: “Oh great, another politician promising change—I’m sure this time it’ll be different!” Tip: Cynicism is like that one friend who brings an umbrella to a wedding—not because they checked the weather, but because they just know something will go wrong.