Valgus deformity, also known as the knock-knee deformity, is a condition where the bones of the leg bend inward at the knee. There are various synonyms used for this condition, including genu valgum, tibial valgus, lower limb valgus, and knee valgus. Genu valgum is a Latin term used to describe valgus deformity, while tibial valgus specifies that the deformity is located in the tibia bone. Lower limb valgus is a broader term that includes all the bones of the lower leg, while knee valgus emphasizes the location of the deformity in the knee joint. Overall, these synonyms are used interchangeably depending on the context of the medical condition.