opinion vs belief

opinion and belief both are nouns.

Word	Noun	Adjective	Verb	Adverb
opinion	Yes	No	No	No
belief	Yes	No	No	No

As nouns, belief is a hypernym of opinion; that is, belief is a word with a broader meaning than opinion:

opinion: a personal belief or judgment that is not founded on proof or certainty
belief: any cognitive content held as true

As nouns, belief is a hypernym of opinion; that is, belief is a word with a broader meaning than opinion:

opinion: a belief or sentiment shared by most people; the voice of the people
belief: any cognitive content held as true

As nouns, opinion and belief are synonyms defined as:

Other synonyms of opinion include feeling, impression, notion.

opinion (noun)	belief (noun)
the reason for a court's judgment (as opposed to the decision itself)	any cognitive content held as true
a personal belief or judgment that is not founded on proof or certainty	a vague idea in which some confidence is placed
a belief or sentiment shared by most people; the voice of the people
a vague idea in which some confidence is placed
the legal document stating the reasons for a judicial decision
a message expressing a belief about something; the expression of a belief that is held with confidence but not substantiated by positive knowledge or proof