Rhetoric is the art of using language effectively and persuasively [convincingly]. It involves using persuasive techniques to influence or persuade an audience.
For example, a politician may use rhetoric to deliver a powerful speech that convinces people to vote for them. In this case, the politician may use emotional appeals, logical arguments, and hyperboles [deliberate exaggerations] to persuade the audience.
Very Simple Definition:
Rhetoric is the skill of using words to convince people of something.
For example, when someone tells a friend that they should try a new restaurant because the food is delicious and they “don’t want to miss it”, they are using rhetoric to persuade their friend to go.