idioms using “blue”

Blue

Sad

“Let’s try to cheer up Sadako-san. She seems quite blue these days.”

Sing the blues

To feel sorry for oneself, to complain

“Edogawa-san has been singing the blues for months now about his new boss.”

Once in a blue moon

Rarely

“Sakiguchi-san is only late once in a blue moon so there’s no need to reprimand her.”

Out of the blue

Without warning

“Sadato-san just mentioned, out of the blue, that she is getting married next week.”

Blue sky

Assuming perfect conditions

“This is a blue sky forecast. Perhaps we should prepare a more realistic one for the sales meeting.”