It’s an adverb and it means in a way that was not expected, anticipated or foreseen. So if something happens totally out of the blue, then it happens unexpectedly.
When offered a second helping of pie Malcolm unexpectedly declined.
by AKACroatalin December 8, 2016
Get the Unexpectedly mug.
The favorite adverb of major news organizations when describing dreary economic news since 2009. It is believed to have originated around May 19, 2009, when Reuters reported "new U.S. housing starts and permits unexpectedly fell to record lows in April . . . denting hopes that stability in the housing market was imminent." Has since been incorporated into the style book of the Associated Press, as well as other journalistic entities.

Anticipated to remain in the forefront of economic reporting until the end of 2016, when it will "unexpectedly" disappear from the landscape.
"The pace of expansion in the U.S. manufacturing sector unexpectedly slowed in March, according to an industry report released on Monday."--Reuters, 4/1/13

"U.S. manufacturing unexpectedly contracted in November, falling to its lowest in over three years ..."--Reuters, 12/3/12

"Previously owned U.S. home sales unexpectedly dropped in March as a lean supply of properties kept the industry from generating a stronger recovery."--Bloomberg, 4/22/13

" Employers added fewer jobs than forecast in November and the unemployment rate unexpectedly increased ..."--Washington Post, 12/3/10
by RobinGoodfellow1 April 28, 2013
Get the unexpectedly mug.
A person who arrives at an event/gathering in an inappropriately advanced stage of inebriation, and attempts to socialize with the other attendees as if nothing were out of the ordinary, is "unexpectedly drunk"
Antoine arrived at the wedding rehearsal a few minutes late, acting more relaxed and jovial than usual. It wasn't until he vomited on the bride's father, and attempted to use the bride's sister as a handkerchief, that people realized he was actually unexpectedly drunk.
by FriendOrFlake July 21, 2014
Get the Unexpectedly Drunk mug.