What is the Literal meaning of out of the blue?

Answer 1

"Out of the blue" probably originates from the rare phenomenon of a lightning bolt that seems to come from a clear blue sky -- actually from a thunder cell too distant to be seen -- and it means "completely unexpected." Broadly, it alludes to the idea of something coming out of nowhere - and a clear blue sky is devoid of anything other than air.

Answer 2

It means just randomly
The image here is of something falling out of the blue sky. It is something that happens totally unexpectedly. Another version of this is "a bolt from the blue," or "out of left field." You might hear "My boss scheduled a meeting out of the blue, and I had to go in on my day off."

Answer 3

A Thesaurus will do that, meaning unpredicted, unexpected, unforeseen, unplanned and unprepared

Answer 4

"Out of the blue" means something came as a total surprise

Answer 5

Something that is a total surprise.