Possible Clues:

• Greek character, attention-seeker captivating male friend, briefly
• Character is a moronic sort
• Greek character's poetic appeal before president leaves America for Italy
• Moronic (anag) — letter from Greece
• Letter between xi and pi
• A letter of the Greek alphabet which is hardly ever used in mathematical notation
• Old man holding sound-enhancing device — a character!
• Greek letter o
• Greek character's order, constant in golf club
• Order press to cover key letter from Plato