FASTEN TIGHTLY is an action that can be accomplished in a variety of ways. The crossword solutions SECURE (6 letters), BRACE (5 letters), and LASH (4 letters) all describe different methods of fastening something tightly. SECURE implies the use of a lock or other device to keep something in place, while BRACE suggests the use of a support structure to hold something firmly. LASH, on the other hand, implies the use of rope or straps to bind something securely. All three solutions are valid ways of fastening something tightly.