preconceived idea vs preconception

preconceived idea and preconception both are nouns.

Word	Noun	Adjective	Verb	Adverb
preconceived idea	Yes	No	No	No
preconception	Yes	No	No	No

As nouns, preconceived idea and preconception are synonyms defined as:

preconceived idea and preconception: an opinion formed beforehand without adequate evidence

Other synonyms of preconceived idea include parti pris, preconceived notion, preconceived opinion, prepossession.

preconceived idea (noun)	preconception (noun)
an opinion formed beforehand without adequate evidence	an opinion formed beforehand without adequate evidence
	a partiality that prevents objective consideration of an issue or situation