The term 'Hardy Boy' is a reference to the fictional detective series of books written by Edward Stratemeyer and published under the pseudonym Franklin W. Dixon. The series follows the adventures of two teenage brothers, Frank and Joe Hardy, as they solve mysteries and crimes. The crossword solution for the term 'Hardy Boy' is 'ANDY', which is the name of the boys' father, Andrew Hardy. ANDY is a private detective who helps his sons in their investigations.