adj. 25B6; adjective
he arrived looking cheerful : HAPPY, jolly, merry, bright, glad, sunny, joyful, joyous, light-hearted, in good/high spirits, full of the joys of spring, sparkling, bubbly, exuberant, buoyant, ebullient, cock-a-hoop, elated, gleeful, breezy, cheery, jaunty, animated, radiant, smiling; jovial, genial, good-humoured; carefree, unworried, untroubled, without a care in the world; informal upbeat, chipper, chirpy, peppy, bright-eyed and bushy-tailed, full of beans; dated gay; formal jocund; poetic/literary gladsome, blithe, blithesome.
a cheerful room : PLEASANT, attractive, agreeable, cheering, bright, sunny, happy, friendly, welcoming.
sad.