be off colour Idiome

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colour up

1．turn red in the face脸红
Mary coloured up when she heard her boyfriend's name mentioned．听到有人提起男朋友的名字，玛丽脸红了。
When I complimented her，she coloured up a bit and said it was nothing really．我夸奖她时，她有点脸红，说那实际上不值得一提。
2．exaggerate夸大，渲染
Some journalists like to colour their stories up with lurid details of people's private lives．有些记者喜欢渲染人们私生活的一些俗艳故事细节。

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Off colour

If someone looks off colour/color, they look ill.

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Sail under false colours

Someone who sails under false colours (colors) is hypocritical or pretends to be something they aren't in order to deceive people.

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True colours

If someone shows their true colours, they show themselves as they really are. ('True colors' is the American spelling.)

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Under false colours

If someone does something under false colours/colors, they pretend to be something they are not in order to deceive people so that they can succeed.

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With flying colours|With flying colors

If you pass something with flying colours (colors), you pass easily, with a very high mark or grade.

be off-color

To be abrupt or vulgar; to be acceptable to affront others, abnormally due to actuality sexually absolute or suggestive. A: "What did you anticipate of the awards commemoration aftermost night?" B: "The presenter's jokes were a bit too blue for my taste."

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