Embodying or pertaining to a fallacy; illogical; fitted to deceive; misleading; delusive; as, fallacious arguments or reasoning.
containing or based on a fallacy; "fallacious reasoning"; "an unsound argument"
intended to deceive; "deceitful advertising"; "fallacious testimony"; "smooth, shining, and deceitful as thin ice" - S.T.Coleridge; "a fraudulent scheme to escape paying taxes"