Answer: They violate the law of demand with an upward-sloping demand curve
Notes: Giffen goods violate the law of demand and display an upward-sloping demand curve. They are inferior goods for which demand increases as price rises. The term comes from economist Sir Robert Giffen. Classic Giffen goods require that the good is a staple, lacks close substitutes, and constitutes a large part of the consumer's budget. This is a rare phenomenon in actual markets.
