It means that it was random, like out of nowhere.
It refers to the "bolt from the blue" a lightning strike from so far away that the cloud is unseen, and it means "coming unexpectedly, and from an unlikely source."
"Out of the blue" refers to 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."
Does the literal meaning make no sense? Then it's an idiom. Have you ever seen anyone really have a blue face? Nope.
surprise, idea, shock
Unless "the blue" is followed by a noun (e.g. the blue sky), blue is a noun, and the is an article.(e.g. the idiom into the blue, meaning parts unknown, literally the sky).
"To be" is not an idiom - it's a verb.
Pest is not an idiom. It's a word.
it means a highly valued asset.
Does the literal meaning make no sense? Then it's an idiom. Have you ever seen anyone really have a blue face? Nope.
surprise, idea, shock
It means the favorite or favored person in the group. A similar idiom is "fair haired child."
'Out of the blue' is a terse form of the expression 'out of a clear blue sky' (to mean 'unexpectedly, without foreshadowing'). It is not really a figure of speech, but an idiom. ('idiom':: an established expression in a language where the meaning is not necessarily what one would anticipate from the given meaning of the individual words).
Unless "the blue" is followed by a noun (e.g. the blue sky), blue is a noun, and the is an article.(e.g. the idiom into the blue, meaning parts unknown, literally the sky).
Needless to say the sky is blue! This is an idiom. Meaning that it is given or obvious.
"To be" is not an idiom - it's a verb.
Pest is not an idiom. It's a word.
The idiom "apple shiner" means the teacher's pet.
"Feeling blue" IS an idiom - you cannot literally feel the color blue! Feeling blue means that you're sad.
The meaning of the idiom in the pink of health means being in good health.