Related Clues:

• Hard-shelled fruit
• Seed with hard shell and firm kernel
• Hard-shelled fruit or informal eccentric
• Seed with hard shell
• Large, hard-shelled seed
• Student who is ridiculed for studying excessively
• Eccentric person
• Hard fruit or informal lunatic
• Intelligent but single-minded expert
• 'Almond or cashew, say (3)'
• One might be wanting to be one
• Well, it doesn't sound this way
• How one gets noise by the yard from this little bird
• A hard case for 1 down
• The case is hard for one by a washer