Source : Webster's Revised Unabridged Dictionary (1913)

Uncertainly \Un*cer"tain*ly\, adv.
   In an uncertain manner.

Source : WordNet®

uncertainly
     adv 1: in an unsteady manner; "he walked unsteadily toward the
            exit"; "The wounded soldier was swinging unsteadily on
            his legs" [syn: {unsteadily}, {falteringly}] [ant: {steadily}]
     2: showing lack of certainty; "he paused uncertainly"