Possible Clues:

• Literally, 'to God'
• 'Goodbye, Luc!'
• Silly idea: Schubert's Fourth the last word?
• **Parting word
• Twenty-seven states having passed bill, one left, making this?
• Chic "Bye"
• Farewell from a princess with international group
• 'Bye-bye, mon ami'
• So long a day that is universal
• Make departure in a university -- farewell