John —, author of 1728 stage work The Beggar's Opera (3)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
gay
(Other definitions for gay that I've seen before include "Brightly coloured" , "Writer of The Beggar's Opera" , "Homosexual" , "Light-hearted, carefree" , "Merry" .)