The antonyms for the phrase "singing blues" can be upbeat or cheerful. Alternatively, the words could be optimistic, joyous, or happy. In contrast to singing blues, the antonyms could be lively, energetic, or carefree. Similarly, the opposite of singing blues could be merry, elated, or contented. Instead of singing the blues, one could be singing a happy tune or a breezy melody. Overall, the antonyms for singing blues suggest a mood of positivity and happiness, in contrast to the lamenting, sorrowful tone of blues music.