false vs fictitious

false and fictitious both are adjectives.

Word	Noun	Adjective	Verb	Adverb
false	No	Yes	No	Yes
fictitious	No	Yes	No	No

As adjectives, false and fictitious are synonyms defined as:

Other synonyms of false include assumed, fictive, pretended, put on, sham.

false (adjective)	fictitious (adjective)
not in accordance with the fact or reality or actuality	adopted in order to deceive
not genuine or real; being an imitation of the genuine article	formed or conceived by the imagination
adopted in order to deceive
designed to deceive
(used especially of persons) not dependable in devotion or affection; unfaithful
arising from error
inaccurate in pitch
deliberately deceptive
erroneous and usually accidental
inappropriate to reality or facts

false (adverb)	fictitious (adverb)
in a disloyal and faithless manner