definition of
fallacious

[1] #1 fallacious s. [unsound] containing or based on a fallacy; "fallacious reasoning"; "an unsound argument". wn

[2] #2 fallacious s. [deceitful, fraudulent] intended to deceive; "deceitful advertising"; "fallacious testimony"; "smooth, shining, and deceitful as thin ice" - S.T.Coleridge; "a fraudulent scheme to escape paying taxes". wn

[3] #3 fallacious s. based on an incorrect or misleading notion or information; "fallacious hope". wn