Which word is a synonym for "happy"?

The word "joyful" is synonymous with "happy" because it describes a state of intense happiness and pleasure. When someone is joyful, they experience a deep sense of contentment and delight, which aligns perfectly with the meaning of happiness. This connection makes "joyful" an appropriate substitute for "happy" in various contexts, whether in writing or conversation.

The other options do not convey the same positive emotion associated with happiness. "Sad" and "angry" indicate negative emotions, while "ecstatic," although conveying a strong positive emotion, suggests an even higher level of happiness that may not be fitting in all contexts. Hence, "joyful" is the most suitable choice as a synonym for "happy."