Related Clues:

• Head is crazy person
• Fanatic beheaded king
• Almond fanatic?
• Biscuit enthusiast
• Head teachers, once obsessive
• Cashew or pecan, eg
• Fruit barrel turned upside-down
• Crack it to eat the insides
• It might be tough to crack
• Pecan or acorn
• Tidbit in 6-Across
• Tree seed one can eat