Not plausible; not credible
Not conclusive or final; not leading to a definite result
Weak or ineffectual:
Of dubious morality or respectability:
Open to or viewed with suspicion:
Not to be believed; incredible:
Lacking in vigour or expression.
Not likely to happen.
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 likely; improbable.
Showing clearly the excellence or superiority of a competitor:
Find another word for unconvincing. In this page you can discover 18 synonyms, antonyms, idiomatic expressions, and related words for unconvincing, like: flimsy, implausible, inconclusive, lame, questionable, suspect, unbelievable, weak, improbable, inconceivable and incredible.