- Today's Word
Fallacious
Fallacious
fuh-LAY-shus
Definition
(adjective) Based on a mistaken belief or containing logical errors.
Example
Her argument was persuasive but ultimately fallacious.
Word Origin
Late 15th century: from Latin fallaciosus, from fallere, meaning “to deceive.”
Fun Fact
Fallacious is the go-to word for arguments that sound solid at first—until you scratch the surface. It’s often used in logic, law, and debate to call out flawed reasoning, like straw man arguments or false dilemmas. In politics, marketing, and social media, fallacious reasoning spreads fast, which is why the word often shows up in fact-checking articles. It’s not about lying outright—it’s about logic that doesn’t hold up.