What's the difference between rejoice and happy? happy is the state of emotion a person can be in rejoice is a verb. For example when a person is happy they do rejoice. -He rejoiced when he found out it was a boy. This statement explains that he is happy already because of his actions of rejoicing. -You will rejoice. This statement a person will become happy or something will make them happy, hence cause them to rejoice

rejoice = verb happy = adjective