transitive. gen. To establish the genuineness or validity of (a person or thing); to show to be such as is asserted or claimed. Obsolete.

To prove or demonstrate (a statement, a fact) by argument, reasoning, putting forward evidence or… transitive. With object and infinitive clause…

To demonstrate or prove any quality, property, or predicate, of a person or thing: i.e. that the person or thing is possessed of such quality, etc…

with complement. To show or prove practically (a thing or person) to be (so and so).