The term 'trunk fastener' can be solved by two crossword solutions: HASP (4 letters) and CORSET (6 letters). A HASP is a type of fastener that consists of a metal loop with a hinged pin or staple. It is typically used to secure a door, lid, or trunk. A CORSET is a type of clothing that is designed to shape and support the body. It is usually made of stiffened fabric and is fastened with laces or hooks. Both the HASP and CORSET are used to fasten trunks and other items securely.