Possible Clues:

• Lose pin (anag.)
• Greek letter - pinoles (anag)
• Greek character gets over speech defect in time
• Piles on unfortunate character from abroad
• … letter spoiled by one slip
• 5th letter of the Greek alphabet
• Is Latin? Nope, different — a Greek letter
• Symbol of electromotive force
• Fifth letter of Greek alphabet
• Greek character rebuilt pen enclosing grain store