Do you like to tell lies? Then you're deceitful — someone who's untrustworthy, two-faced, or fraudulent.
Being called deceitful is not a compliment: deceitful words are misleading and deceitful people tend to lie or deceive others. You can say a corrupt business is deceitful, and a two-faced politician is deceitful. A deceitful story is meant to trick you in some way, and a deceitful friend is no friend at all — they're someone you shouldn't trust. Deceitful is the opposite of honest.