Someone who is extravagant spends more money than they can afford or uses more of something than is reasonable.

Can you tell me the meaning of extravagant?

more expensive than is necessary or reasonable, or having the characteristics of being expensive: Company executives enjoyed an extravagant lifestyle.

Is extravagant positive or negative?

Extravagant. Positive: Your gift to the foundation was too generous. Negative: Your gift to the foundation was too extravagant. To compliment someone's generosity is to offer high praise.