Possible Clues:

• Gesture made by foreigner upset mother, unfortunately
• Act of obeisance
• Big bow
• Mother, too bad, is back to greet this in a respectful sort of way
• Graduate regrettably turning back in greeting
• Greeting, I'm sorry to say, upset a mourner initially
• Greeting with a bow
• Oriental salutation meaning 'peace'
• Greeting head of state with panic, say
• An oriental greeting