Antonyms are words with opposite meanings to a given word. Morose means being sullen, gloomy, or ill-humored. Therefore, antonyms for "was morose" could include words such as happy, cheerful, joyful, optimistic, buoyant, and vivacious, as they are all contrasting emotions. Other antonyms could be delighted, elated, spirited, lively, and exuberant. These words are all positive and would create a direct opposites to the negativity of being morose. So, if you want to express the opposite feeling or emotion of being morose, you can use any of the antonyms mentioned above.