Poshlost is a fancy word to describe something that is tacky or tasteless. Imagine you are drawing a picture and someone tells you to use all the colors in your crayon box without any thought or plan. The result would be very messy and unattractive. That's what poshlost means. It's like using too many colors without a plan and creating something that is cheap and unimpressive. So, poshlost is when people try to be fancy by doing things that are not classy or elegant. It's kind of like pretending to be something you're not, but doing it in a very obvious and unappealing way. So, it's always better to be yourself and not try so hard to impress others.