Not likely to be true.
The definition of doubtful is suspicious, unclear or unsure.
The definition of dubious is something that is unlikely to be true.
(Informal) Inspiring doubt or suspicion:
Ill-conceived and inadequate; ineffectual
Open to or viewed with suspicion:
Not functioning normally or well
So implausible as to elicit disbelief; unbelievable:
Not dependable or reliable; questionable
Having little bodily flesh or fat; lean or slender.
Not solid or heavy; flimsy; light
Not determined by reason; capricious; arbitrary; irrational.
Persuasive or ingratiating, especially in an effort to deceive.
Within the realm of credibility; plausible:
Capable of eliciting belief or trust.
Not excessive or extreme; fair:
Not promising; likely to fail.
Find another word for implausible. In this page you can discover 37 synonyms, antonyms, idiomatic expressions, and related words for implausible, like: inconceivable, farfetched, improbable, ridiculous, unconceivable, impossible, unlikely, doubtful, dubious, fishy and flimsy.