Knock knees, also known as genu valgum, is a condition in which the knees touch or are close together but the ankles are apart. This deformity is often caused by the inward or medial tilting of the lower leg bone due to a misalignment of the knee joint. While the term "knock knee" is commonly used to describe this condition, it's not the only phrase that people use. Other synonyms for knock knees include bow-leggedness, knee valgus, genu valgum, and bandy-legged. Identifying and understanding different phrases for knock knees can help in better explaining the condition to healthcare professionals and others.