Source : Webster's Revised Unabridged Dictionary (1913)

Blithe \Blithe\ (bl[imac][th]), a. [AS. bl[=i][eth]e blithe,
   kind; akin to Goth. blei[thorn]s kind, Icel. bl[=i][eth]r
   mild, gentle, Dan. & Sw. blid gentle, D. blijd blithe, OHG.
   bl[=i]di kind, blithe.]
   Gay; merry; sprightly; joyous; glad; cheerful; as, a blithe
   spirit.

         The blithe sounds of festal music.       --Prescott.

         A daughter fair, So buxom, blithe, and debonair.
                                                  --Milton.

Source : WordNet®

blithe
     adj 1: lacking or showing a lack of due concern; "spoke with blithe
            ignorance of the true situation"
     2: carefree and happy and lighthearted; "was loved for her
        blithe spirit"; "a merry blithesome nature"; "her
        lighthearted nature"; "trilling songs with a lightsome
        heart" [syn: {blithesome}, {lighthearted}, {lightsome}]