I chose "puzzle" as a medium difficulty word because it contains an uncommon letter (z) that appears twice, which adds challenge. With only one vowel (u), players will need to work harder to fill in the blanks. The word is 6 letters long, meeting the length requirement, and it's a common English noun that most people recognize, but isn't immediately obvious to guess in Hangman. The double consonant and limited vowels make it tricky without being unfairly difficult.