Seven colours make up a rainbow: Red, Orange, Yellow, Green, Blue, Indigo, and Violet. English has an idiom for nearly all these colours.
Red
Red can be a symbol for danger or problems such as “to be in the red” (to be in debt). It can also mean to discover someone in the act of doing something wrong or bad and so we “catch him or her red handed”. However, the colour red also represents good; to treat someone royally, is to “roll out the red carpet” for him or her, while a “red letter day” is a special day.
Orange
Unfortunately, despite its cheerful colour, there are no idioms for orange. However, we use the expression “like apples and oranges” when we want to compare two very different things.
Yellow
While yellow used to represent Chinese emperors in ancient times, it generally has a bad meaning in English as in “he is yellow bellied” (he is a coward). But, if we darken this colour a little, we have the idiom “golden opportunity” (a good opportunity) and if something is really good, we say it is as “good as gold”.
Green
We can be “green with envy” (a little jealous) and think that “the grass is greener on the other side of the fence” believing that others are more fortunate than we are.
Blue
The blue sky gives rise to a number of idioms such as “out of the blue” (come unexpectedly) and “once in a blue moon” (rarely). We can also “feel a little blue” (a little miserable), while to be “blue with cold” means you are very, very cold. I’m not sure why, but “the blues” is soulful jazz!
Indigo
Alas, we don’t have any idioms for indigo, which is a kind of dark blue and a popular colour used in paintings.
Violet
Violet is a vivid purple. Tt is the name of a small and pretty woodland flower. However if you are a “shrinking violet”, you are shy and don’t like the to be in the limelight!
Next time you see a rainbow, think of these idioms – perhaps you can create some new and original ones of your own!