Deceitful means deliberately lying or misleading others to trick them. A deceitful person doesn't just make mistakes or get facts wrong: they intentionally hide the truth or twist it to serve their own purposes.

When someone is deceitful, they might tell you one thing while knowing something completely different is true. A deceitful friend might promise to help you study but secretly plan to skip out. A deceitful salesperson might describe a broken toy as “gently used” when they know it doesn't work at all. In fairy tales, deceitful characters often wear disguises or make false promises to trap the hero.

Being deceitful is different from being tactful or keeping a secret. If you don't mention that you dislike your aunt's cooking, that's being polite. But if you tell her it was delicious when she asks directly, that edges toward deceit. If you actively plan ways to trick someone for your own benefit, you're being truly deceitful.

Deceitful behavior destroys trust, which is why it damages relationships so deeply. Once people realize someone has been deceitful, they question everything that person says, even when that person might be telling the truth.