preconceived opinion vs prepossession

preconceived opinion and prepossession both are nouns.

Word	Noun	Adjective	Verb	Adverb
preconceived opinion	Yes	No	No	No
prepossession	Yes	No	No	No

As nouns, preconceived opinion and prepossession are synonyms defined as:

preconceived opinion and prepossession: an opinion formed beforehand without adequate evidence

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

preconceived opinion (noun)	prepossession (noun)
an opinion formed beforehand without adequate evidence	an opinion formed beforehand without adequate evidence
	the condition of being prepossessed