It's gonna take us a long to discriminate the meanings of some words.
Take ladies as an example. Most of them wish to have a good figure and a perfect size. In particular, they wish to be slim. If you go to super market, you will see some merchandises such as "Slim Fast".
In the everyday English, we also hear the word "skinny". By skinny people usually mean extremely slim. Slim is a good word, but skinny is not. I asked an American guy for distiguishing the meaning of these two words. His answer is straightforward: " If a girl is skinny, I don't think you will be interested in her. However, a girl with a slim figure is most likely sexy."