Synonyms of lighthearted

1 Syllable

bright, gay, joyous, glad, buoyant, yoyo

2 Syllables

blither, blithe, jollying, feelgood, jovial, cheerful, larking, merry, coltish, merrier, merriest, gleeful, jocund, sprightly, grooving, zappy, mirthful, festal, zingy, jollier, zingier, blithest, sunny, playful, happy, booner, laid-back, yo-yo, gladdest, joyful, tickled, upbeat, jokey, waggish, chirpy, jolly

3 Syllables

hopeful, mercurial, riproaring, unworried, rollicking, rip-roaring, gladsome, festive, lightsome, vivacious, debonair, quicksilver, spirited, free-minded, insouciant, resilient, lively, jocular

4 Syllables

volatile, frolicsome, blithesome, high-spirited, effervescent, saturnalian, bubbleheaded, conversable, expansive

5 Syllables

carnivalesque, happy-go-lucky