fallacious vs deceitful

fallacious and deceitful both are adjectives.

Word	Noun	Adjective	Verb	Adverb
fallacious	No	Yes	No	No
deceitful	No	Yes	No	No

As adjectives, fallacious and deceitful are synonyms defined as:

Other synonyms of fallacious include fraudulent.

fallacious (adjective)	deceitful (adjective)
involving deception	marked by deliberate deceptiveness especially by pretending one set of feelings and acting under the influence of another
based on an incorrect or misleading notion or information	involving deception
containing or based on a fallacy