Slim: you can still touch muscles Skinny: you can touch bones haha...

I agree that "slim" has a much more positive conotation than "skinny." However, working at a gym, I often hear people say, "I want to be as skinny as her!" or "You are so skinny! What's your secret?" It is not always meant or taken as an insult. But to be on the safe side, use "slim" if you are speaking of someone's physique in a positive way. You will probably not hear anyone say, "She is too slim." But you will often hear, "She is too skinny."

Both have same meaning, but their effect is different. If you refer to a woman as skinny it is an insult. you need also to be a bit careful telling someone they look "thin" because the woman might think what you really mean is "skinny". Slim on the other hand is a much more positive word which implies that someone looks healthy and not overly thin or skinny.

"skinny" - very thin & bony "slim" - shapely body

Slim is beautiful and healthy. Skinny doesn't necessary look beautiful and definitely not healthy!!