The term 'THING TO BE CRACKED' can be solved by the crossword solution CIPHER, which is a six-letter word. A CIPHER is a type of code or encryption used to protect information from being read by unauthorized individuals. It is usually composed of a series of letters, numbers, and symbols that are used to represent a message or data. Ciphers are often used in cryptography, which is the practice of using codes and ciphers to protect sensitive information.