opinion

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A belief or conclusion held with confidence but not substantiated by positive knowledge or proof: synonym: view.
• noun A judgment based on special knowledge and given by an expert.
• noun A judgment or estimation of the merit of a person or thing.
• noun The prevailing view.
• noun A court's formal, usually written statement explaining its reasons for its decision in a case.
• noun An attorney's formal, usually written statement giving an assessment of how the law should be or is likely to be applied in a particular situation.
• noun A piece of testimony that is not usually admissible when given by a layperson, as in contrast to an opinion given by an expert witness.

from The Century Dictionary.

• To think; opine.
• noun A judgment formed or a conclusion reached; especially, a judgment formed on evidence that does not produce knowledge or certainty; one's view of a matter; what one thinks, as distinguished from what one knows to be true.
• noun Specifically — The estimate which one forms regarding persons or things with reference to their character, qualities, etc.: as, to have a poor opinion of a man's honesty, or of the efficiency of some arrangement or contrivance; a poor opinion of one's self.
• noun Favorable judgment or estimate; estimation.
• noun Judgment or persuasion, held more or less intelligently or firmly; conviction: often in the plural: as, one's political opinions.
• noun A judgment or view regarded as influenced more by sentiment or feeling than by reason; especially, views so held by many at once, collectively regarded as constituting a social force which tends to control the minds of men and determine their action.
• noun Common notion or idea; belief.
• noun Rumor; report.
• noun A professional judgment on a case submitted for examination: as, a legal or medical opinion.
• noun Standing in the eyes of one's neighbors or society at large; reputation; especially, favorable reputation; credit.
• noun Dogmatism; opinionativeness.
• noun Synonyms Belief, Conviction, etc. (see persuasion); sentiment, notion, idea, view, impression.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb obsolete To opine.
• noun That which is opined; a notion or conviction founded on probable evidence; belief stronger than impression, less strong than positive knowledge; settled judgment in regard to any point of knowledge or action.
• noun The judgment or sentiment which the mind forms of persons or things; estimation.
• noun obsolete Favorable estimation; hence, consideration; reputation; fame; public sentiment or esteem.
• noun obsolete Obstinacy in holding to one's belief or impression; opiniativeness; conceitedness.
• noun (Law.) The formal decision, or expression of views, of a judge, an umpire, a counselor, or other party officially called upon to consider and decide upon a matter or point submitted.
• noun to think; to judge.
• noun [Obs.] to agree with.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A belief that a person has formed about a topic or issue.
• verb transitive, archaic To have or express as an opinion.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a belief or sentiment shared by most people; the voice of the people
• noun the legal document stating the reasons for a judicial decision
• noun the reason for a court's judgment (as opposed to the decision itself)
• noun a personal belief or judgment that is not founded on proof or certainty
• noun a vague idea in which some confidence is placed
• noun 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