The Collaborative International Dictionary of English v.0.48:

Seraphic \Se*raph"ic\, Seraphical \Se*raph"ic*al\, a. [Cf. F.
   s['e]raphique.]
   Of or pertaining to a seraph; becoming, or suitable to, a
   seraph; angelic; sublime; pure; refined. "Seraphic arms and
   trophies." --Milton. "Seraphical fervor." --Jer. Taylor. --
   Se*raph"ic*al*ly, adv. -- Se*raph"ic*al*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

seraphic
    adj 1: of or relating to an angel of the first order; "he
           imagined a seraphic presence in the room" [syn:
           seraphic, seraphical]
    2: having a sweet nature befitting an angel or cherub; "an
       angelic smile"; "a cherubic face"; "looking so seraphic when
       he slept"; "a sweet disposition" [syn: angelic,
       angelical, cherubic, seraphic, sweet]

Moby Thesaurus II by Grady Ward, 1.0:

59 Moby Thesaurus words for "seraphic":
   Christlike, Christly, Elysian, God-fearing, admirable, adorable,
   angelic, archangelic, beatified, blissful, canonized, caressable,
   celestial, charming, cherubic, cuddlesome, divine, empyrean,
   ethereal, glorified, godlike, godly, godly-minded, good, heavenly,
   holy, holy-minded, honest, in glory, just, kissable, likable,
   lovable, lovely, lovesome, martyred, moral, otherworldly, pure,
   pure in heart, purehearted, redeemed, right-minded, righteous,
   sainted, saintlike, saintly, saved, spiritual, spiritual-minded,
   straight, sublime, sweet, unearthly, unworldly, upright, virtuous,
   winning, winsome