The Oxford Thesaurus An A-Z Dictionary of Synonyms - blitheadj.

1) blissful, happy, cheerful, joyous, merry, light-hearted, well-pleased, delighted, gay, joyful, elated, jubilant: His spirit was blithe and his heart unquenchable. 2) happy-go-lucky, insouciant, heedless, carefree, unconcerned, blas‚, casual, detached, indifferent, uncaring, careless: She goes through life with a blithe disregard for the feelings of others.