Blithe, a.
Etymology: [AS. bli blithe, kind; akin to Goth. blei kind, Icel. bli mild, gentle, Dan. & Sw. blid gentle, D. blijd blithe, OHG. blidi 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.
Shades of meaning
Fernald has no entry of its own for blithe; he lists it under happy.
He lists it without comment; the entries above explain its neighbors.