Disinformation is deliberately conveying false information. As for misinformation, in some cases, it's when someone shares false information, but unintentionally, without knowing that it's false. Malinformation is really when someone knowingly passes on information that is false to mislead the public and create mayhem.
Yes, there are a number of definitions. I'm giving you the most commonly used ones, but the wording can vary.
You may have seen the recent report about a centre at McGill University, in which Mathieu Lavigne and his colleagues spell out definitions for these terms. The report includes key references and recommendations for misinformation and disinformation in an electoral context.