Related Clues:

• Hardly plentiful
• Straight's partner
• Like cabs on a rainy day
• Limited
• At a premium
• AAA, maybe
• Hard to find
• Slender
• Infrequent
• Like hen's teeth, so to speak
• Insufficient
• Like capital letters in many E. E. Cummings poems
• Tightly defined
• Taper
• Like cabs on a rainy day, seemingly