Black is a lot of things, but "discreet" is usually not one of them. The little black dress, black sheep, black Friday; all have black in them, but they represent different things entirely.
When it comes to black, there is a lot of debate regarding the color theory and psychology around it – whether it's a color or not, and people's perception of it. It would interest you to know that because true black absorbs all light, it is achromatic (not actually a color) and is used to represent darkness.
Black was the first color the early men used to scribble and illustrate their art on cave walls with. And ever since, it has been the default color we use for most things – especially print paperwork.
It is safe to say black is the mother of earthly mysteries and complexities. This universal color may look the same to most, but everybody has an avid interpretation of what black means – especially when it comes to clothing.
The color black is a shade/color that comes off as mysterious, serious, prestigious, and powerful to most people. When worn, it is a symbol of class, business, elegance, and sexiness while also having an overbearing, even sometimes evil character to it.