Y-front is a term usually used to describe men's underwear that has a flap or pouch in the front. While Y-front is the commonly used term for this type of underwear, there are also several synonyms that you can use. In the United States, it's often referred to as "tighty-whities" because of its close-fitting and white color. In the United Kingdom, Y-fronts are also known as "jockey shorts" because they are similar to underwear worn by horse jockeys. Another term for Y-fronts is "briefs," which is a general term used to describe close-fitting undergarments. Other synonyms for Y-fronts include "whiteys," "tighties," and "skivvies".