speciousness n an appearance of truth that is false or deceptive; seeming plausibility the speciousness of his argument Usage(s) The plot's intrigues are given a sombre speciousness by current events and nimble writing. The speciousness in the argument of our Senatorial and other America Firsters (e. In one story, Glass told readers he had made up a town--"Werty, Iowa"--to test the speciousness of a policy group. Synonym(s) meretriciousness