Source : Webster's Revised Unabridged Dictionary (1913)

Supercilious \Su`per*cil"i*ous\, a. [L. superciliosus, fr.
   supercilium an eyebrow, pride; super over, + cilium an
   eyelid; probably akin to celare to conceal. Cf. {Conceal}.]
   Lofty with pride; haughty; dictatorial; overbearing;
   arrogant; as, a supercilious officer; asupercilious air;
   supercilious behavior. -- {Su`per*cil"i*ous*ly}, adv. --
   {Su`per*cil"i*ous*ness}, n.

Source : WordNet®

superciliously
     adv : with a sneer; in an uncomplimentary sneering manner; "`I
           don't believe in these customs,' he said sneeringly"
           [syn: {sneeringly}, {snidely}]