The Great Impostor, for one
Else clues• Affected one
• Charlatan
• Dude with a 'tude?
• Fraud
• One who affects a false attitude
• One who puts on airs
• One with affected manners
• Phony
• Phony sort
• Phony type
• Pretender
• Show-off
• A person who habitually pretends to be something he is not