The phrase "skinny legs" is an idiomatic expression that refers to having thin or slender legs. It can be used in a positive, neutral or negative context depending on the situation and tone of voice it's said in. For example, if someone says they have skinny legs while complimenting their own appearance, then it means they are proud of their leg shape and consider it an attractive feature. On the other hand, if someone else uses the phrase negatively to describe another person, such as "she has really skinny legs," then it could be interpreted as a negative comment about that person's body image or physical appearance.