imaginary vs fanciful

imaginary is a noun but fanciful is not a noun.

Word	Noun	Adjective	Verb	Adverb
imaginary	Yes	Yes	No	No
fanciful	No	Yes	No	No

As adjectives, imaginary and fanciful are synonyms defined as:

imaginary and fanciful: not based on fact; existing only in the imagination

Other synonyms of imaginary include notional.

imaginary (noun)	fanciful (noun)
(mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1

imaginary (adjective)	fanciful (adjective)
not based on fact; existing only in the imagination	indulging in or influenced by fancy
	having a curiously intricate quality
	not based on fact; existing only in the imagination