The so-called formal dress refers to the formal dress suitable for serious occasions, which is the dress for formal occasions, not for entertainment and home environment. Such as suits, Chinese tunic suits and national costumes.

Black is the best, others can do it, but don't be fancy.

When wearing clothes that look very formal, there are three taboos about clothes.

1. You can't wear a black leather skirt (this is the international standard for prostitutes).

2. It's not just the legs: wear a pair of shoes to wrap the front and back that are easy to grind.

3. You can't add fitness pants under the skirt, you can't wear half a sock, you can make three legs, which is described as malicious segmentation in professional terms.

The above answers refer to Baidu Encyclopedia, which I sorted out after reading. I hope I can help you to some extent.