Source : Webster's Revised Unabridged Dictionary (1913)

Unexpected \Un`ex*pect"ed\, a.
   Not expected; coming without warning; sudden. --
   {Un`ex*pect"ed*ly}, adv. -- {Un`ex*pect"ed*ness}, n.

Source : WordNet®

unexpectedly
     adv 1: in a way that was not expected; "her brother showed up at
            the wedding out of the blue" [syn: {out of the blue}]
     2: without advance planning; "they met accidentally" [syn: {by
        chance}, {accidentally}, {circumstantially}] [ant: {intentionally}]