unpersuasive Synonyms

not convincing insufficient ineffectual ineffective incredible inconclusive inconceivable inadequate improbable implausible lame obscure poor unconvincing unimpressive unbelievable unsatisfactory flimsiest weak vain unsuccessful thin hollow fruitless disputable derisory delicate deficient defective convincer convincing conclusive compelling dissuasive doubtful empty frivolous fragile forceless flimsy flabby feeble faulty faint failing ambiguous