Explanation:

- Extravagant: Describes someone who spends too much money or resources unnecessarily. It's often used to indicate wastefulness or excessive spending.

- Option 1: Thrifty: This means being careful with money, not spending more than necessary. It's often used to describe someone who is frugal or economical.

- Correct Antonym: The opposite of being extravagant.

- Option 2: Deficit: Refers to a shortage or deficiency, typically in financial context, but doesn't directly oppose the idea of lavish spending.

- Option 3: Pauper: Describes a very poor person, but focuses on their financial state, not their spending habits.

- Option 4: Generous: Indicates a willingness to give freely, which doesn't necessarily imply wastefulness, hence not a direct opposite.