legal opinion

opinion formed in accordance with the law

In law, an opinion is usually a written explanation by a judge that accompanies their ruling in a case, laying out the rationale and legal principles that led them to rule as they did. Opinions are usually published at the direction of the court, and to the extent they contain pronouncements about what the law is and how it should be interpreted, they reinforce, change, establish, or overturn legal precedent. Another kind of legal opinion is written by attorneys. It is a formal written statement an attorney prepares for a client, stating the lawyer's reasoned belief about what the law is, how a court would interpret it, or how it applies to specific circumstances posed by the client.
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A statement, usually written by a specialized law firm, required for a new municipal bonds issue stating that the issue is legally acceptable.