Opinion has no simple set of strict antonyms because it means a view or judgment rather than a quality with a direct opposite. In many contexts, the useful contrast is with fact, evidence, data, or another form of information that can be independently checked.
Useful Contrasts by Type of Evidence
- Fact
- Evidence
- Data
- Proof
- Observation
- Finding
- Record
- Verified information
- Objective measure
- Established fact
- Documented result
- Knowledge
- Certainty
Fact
A fact is something that can be established as true, whereas an opinion expresses a judgment or view.
Example: It is a fact that the meeting began at nine; whether it was productive is an opinion.
Evidence
Evidence is information used to support or challenge a claim, including opinions that require justification.
Example: The recommendation should be based on evidence rather than opinion alone.
Data
Data are recorded observations, measurements, or values that can inform an interpretation or opinion.
Example: The data show a decline in response time.
Proof
Proof is evidence or reasoning sufficient to establish a proposition in contexts where proof is possible.
Example: The document provides proof that the payment was made.
Observation
An observation records something noticed or measured, although observations can still be interpreted differently.
Example: The note contains an observation about behaviour, not a judgment about motive.
Finding
A finding is a result reached through investigation or analysis and is usually tied to a stated method or evidence base.
Example: The main finding was consistent across all three groups.
Record
A record documents an event, transaction, statement, or measurement and can be checked independently of personal opinion.
Example: The attendance record confirms who was present.
Verified information
Verified information has been checked against reliable sources or evidence before being accepted.
Example: The briefing separates verified information from unconfirmed claims.
Objective measure
An objective measure is defined independently of the evaluator’s personal preference or impression.
Example: Waiting time was used as an objective measure of access.
Established fact
Established fact emphasises that a point is well supported and not merely a matter of individual judgment.
Example: The date of publication is an established fact.
Documented result
A documented result is an outcome recorded through a traceable process rather than a personal view.
Example: The audit produced a documented result for each test.
Knowledge
Knowledge refers to information or understanding regarded as known, though philosophical definitions of knowledge are more complex.
Example: Professional judgment combines knowledge with experience.
Certainty
Certainty means absence of doubt and contrasts with an opinion only when the opinion is tentative or disputable.
Example: The evidence does not allow certainty about the cause.
Fact and Opinion Are Not Always a Complete Binary
An opinion can be well informed and supported by evidence, while a factual claim can be mistaken if the evidence behind it is poor. The useful distinction is usually between what is being asserted and how it can be checked.
Consensus is not an antonym of opinion: it is agreement among multiple people and can still concern a judgment. Likewise, assertion and conviction are types of claims or beliefs, not opposites of opinion.