fallacious

What does "fallacious" mean?
"Fallacious" describes an argument or belief that is based on mistaken reasoning or a logical error. Imagine a beautiful, sturdy-looking bridge that is actually missing critical support beams; it looks like a valid path, but if you step onto it, it collapses because the underlying structure is unsound. You will typically encounter this word in academic, legal, or journalistic contexts. It is used to point out that someone’s logic is flawed, even if their conclusion happens to be correct or their tone is very persuasive. It is often paired with terms like "reasoning," "logic," or "assumption."
"fallacious" in conversation
Debating a theory
Your argument relies on the idea that everyone agrees with this policy.
Your argument relies on the idea that everyone agrees with this policy.
That’s a fallacious assumption; the survey data shows a clear split.
That’s a fallacious assumption; the survey data shows a clear split.
Used to shut down a weak premise in a debate.
Reviewing a paper
The conclusion is interesting, but the path you took to get there is fallacious.
The conclusion is interesting, but the path you took to get there is fallacious.
I see, I should probably re-examine my evidence.
I see, I should probably re-examine my evidence.
Common in academic feedback regarding logical flow.
"fallacious" in a sentence
His argument was based on a fallacious premise.
His argument was based on a fallacious premise.
It is fallacious to believe that correlation always implies causation.
It is fallacious to believe that correlation always implies causation.
The defense attorney dismantled the prosecutor's case by exposing its fundamentally fallacious logic.
The defense attorney dismantled the prosecutor's case by exposing its fundamentally fallacious logic.