Definition of opinion

• a personal belief or judgment that is not founded on proof or certainty; "my opinion differs from yours"; "what are your thoughts on Haiti?"
• a belief or sentiment shared by most people; the voice of the people; "he asked for a poll of public opinion"
• 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; "his opinions appeared frequently on the editorial page"