Spurious means false or not genuine, even though it may look real, as in a spurious claim. Specious means something that seems plausible or well-reasoned but is actually false or misleading, as in a specious argument. Think of specious as false reasoning that sounds convincing, and spurious as a fake fact.
The core difference
Spurious describes something fake or unfounded; specious describes something that sounds convincing but is actually flawed.
- spurious — false or not genuine, despite appearing real: The report was based on spurious data that could not be verified.
- specious — seemingly plausible or reasonable but actually fallacious: His specious argument convinced the jury until the evidence was checked.
How to tell them apart
The two words often turn up together when someone is dismantling a weak argument, but they describe different faults. A spurious claim is simply untrue or invented, whether or not it sounds convincing — a spurious correlation between two variables, for instance, is a false link, not a persuasive one. A specious argument is the opposite problem: it sounds reasonable and may even be built on real facts, but the logic underneath does not hold up.
One way to remember the difference: specious shares a root with "species" and originally meant good-looking or plausible in appearance, so a specious argument is one that looks good on the surface. Spurious has no such connection to appearance; it simply means fake.
