“Unhappy” means not happy or sad, dissatisfied, or in a state of unhappiness. Some antonyms of “unhappy” are “happy”, “content”, and “cheerful”.
“Happy” is the most obvious antonym. It implies a state of joy, pleasure, and satisfaction. For example, “She was unhappy yesterday, but today she is extremely happy.” This shows the clear contrast between being unhappy and being happy.
“Content” suggests a state of peaceful satisfaction. “He was once unhappy with his job, but now he is content.” Here, “content” indicates a lack of unhappiness and a sense of being at ease.
“Cheerful” refers to being in a good mood, lively, and full of joy. “The room was gloomy when she was unhappy, but now it is filled with cheerfulness.” This highlights the difference between unhappiness and a cheerful disposition.