The Collaborative International Dictionary of English v.0.48:

Supereminent \Su`per*em"i*nent\, a. [L. supereminens, p. pr. of
   supereminere. See Super-, and Eminent.]
   Eminent in a superior degree; surpassing others in
   excellence; as, a supereminent divine; the supereminent glory
   of Christ. -- Su`per*em"i*nent*ly, adv.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "supereminent":
   aggrandized, apotheosized, arch, awesome, banner, beatified, big,
   canonized, capital, cardinal, central, champion, chief, crowning,
   deified, divine, dominant, elevated, eminent, ennobled, enshrined,
   enthroned, exalted, excellent, exquisite, first, focal, foremost,
   gilt-edged, glorified, glorious, golden, grand, great, headmost,
   heavenly, hegemonic, held in awe, high, high and mighty, immense,
   immortal, immortalized, leading, lofty, magisterial, magnificent,
   magnified, main, marvelous, master, mighty, overruling, paramount,
   predominant, preeminent, preponderant, prevailing, primal, primary,
   prime, principal, ranking, ruling, sainted, sanctified,
   sensational, shrined, sovereign, splendid, splendiferous, star,
   stellar, sterling, sublime, super, superb, superexcellent,
   superfine, terrific, throned, topflight, tremendous, wonderful