Possible Clues:

• He finds fault in fancy nicknames
• One who thinks people are motivated by self-interest
• Person who is generally sceptical
• One knows the cost of everything and the value of nothing
• Sneering critic Nancy nicely hides
• 'Mordancy' nicely defining one of her characteristics?
• Misanthrope
• Sent out from constituency for Thomas
• Sarcastic sort
• Sort of Greek philosopher