fictitious vs assumed

fictitious and assumed both are adjectives.

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

As adjectives, fictitious and assumed are synonyms defined as:

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

fictitious (adjective)	assumed (adjective)
adopted in order to deceive	adopted in order to deceive
formed or conceived by the imagination