a bolt from the blue
Something unexpected or surprising. We always thought of Michael as a life-long bachelor, so it certainly was a bolt from the blue when he returned from his vacation sporting a wedding ring!
bolt from the blue
Fig. a sudden surprise. (Alludes to a stroke of lightning from a cloudless sky.) Joe's return to Springfield was a bolt from the blue. The news that Mr. and Mrs. King were getting a divorce struck all their friends as a bolt from the blue.
bolt from the blue
A sudden, shocking surprise or turn of events.
bolt from the blue, a
A sudden, unexpected event, usually of a catastrophic nature. The term refers to a bolt of lightning or thunder that comes from a blue (cloudless) sky and hence is not anticipated. Although “blue” was a poetic allusion to the sky by 1700, the precise expression dates from the early nineteenth century. It appears in Thomas Carlyle’s description of chaotic events of the French Revolution: “Arrestment, sudden really as a bolt out of the blue, has hit strange victims” (1837).