What does implausible mean?
Implausible is an adjective describing something that is not believable because it conflicts with reason, probability, experience, or established facts. It is commonly applied to explanations, claims, stories, and events: an implausible excuse may lack internal consistency, while an implausible theory may contradict what is known. The word is stronger than “unlikely,” since it suggests more than merely low probability; it conveys that a statement is difficult to accept as credible. In conversation, “that seems implausible” is a conventional way to express skepticism without directly declaring something false. Although “improbable” can also mean unlikely, “implausible” places particular emphasis on departures from logic and accepted evidence. The word is useful when describing a claim whose problems are not merely unusual but fundamentally difficult to reconcile with reality.
adjectiveNot plausible or believable; so unlikely that it does not accord with reason, probability, or accepted facts.
- Contrary to reason, probability, or accepted facts; not believable.
- So unusual or unexpected that it appears impossible or highly improbable.
"His explanation for the delay sounded entirely implausible."
"The witness gave an implausible account of what had happened."
"It seems implausible that the project could be completed in a single week."
Once a story becomes implausible, extra detail often makes it less convincing, not more.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does implausible come from?
Implausible was formed in the early 19th century from the Latin prefix im-, meaning “not,” and plausible. Plausible comes from Latin plausibilis, from placere, meaning “to please” or “seem,” and ultimately from placere, “to seem” or “appear.” The related words plausible, plausibility, and plausibly also descend from this Latin root.
Related word forms
How implausible is actually used
Common in formal and informal English. It is often stronger than “unlikely”: “unlikely” can describe a low probability, while “implausible” usually indicates that a claim is difficult to accept because it lacks logical or factual credibility.
Easily confused with implausible
Improbable emphasizes statistical or practical unlikelihood, whereas implausible more often suggests that something conflicts with reason, logic, or credibility.