ExplainerWhy in Chinese culture ‘wearing a green hat’ means man has a cheating wife
In ancient China, green was considered a lowly, degrading colour, labelled a ‘mixed colour’ because it results from blending blue and yellow

The colour that Chinese men dislike the most is perhaps green.
This aversion stems from centuries of tradition in Chinese history, where “wearing a green hat” signifies that a man’s wife has been unfaithful.
Around 2,000 years ago in ancient China, green was regarded as a lowly and degrading colour. It was referred to as a “mixed colour” because it is created by blending blue and yellow.
At that time, the general populace valued five “primary colours” – red, yellow, blue, white, and black – while looking down upon other colours, which they believed were inferior mixtures of these prime hues.

Consequently, emperors, ministers, and mid-level officials donned gowns in one of these esteemed colours, reserving green attire for low-grade officials.