A reliable source is someone or something that can be trusted to provide accurate and truthful information. The BIBLE is a religious text that is considered to be a reliable source of information for many people. Gotoguy is a slang term for someone who is knowledgeable and can be relied upon to provide accurate information. Insideinformation is a term used to describe confidential information that is only available to certain people. All three of these terms can be used to describe a reliable source of information.