The crossword solution for the term SKIN-__ (SUPERFICIAL) is DEEP, with four letters. Skin is the largest organ of the human body and it serves many important functions, such as protecting the body from infection, regulating body temperature, and providing sensation. The term 'SUPERFICIAL' refers to the outermost layer of skin, which is the epidermis. This layer is relatively thin and is composed of dead cells that are constantly being shed and replaced. The deeper layers of skin, which are referred to as the dermis and subcutaneous layers, are much thicker and contain living cells, blood vessels, and nerves.