The term 'clincher' can refer to a variety of different things. A capper (6 letters) is someone who seals a deal or agreement, often with a HANDSHAKE. A VISE (4 letters) is a tool used to hold objects firmly in place. A HANDSHAKE (9 letters) is a gesture of agreement or understanding between two people. Finally, a RING (4 letters) is a symbol of commitment or agreement. All of these terms can be used to describe a clincher, which is an action or object that seals a deal or agreement.