Qimar means gambling in Arabic — any transaction or activity where the outcome depends purely on chance and one party wins at the expense of another. It is strictly prohibited (haram) in Islamic law.
In Islamic finance, any financial product that resembles gambling — where gains are uncertain and speculative — is considered Qimar. This includes lottery tickets, casino games, and highly speculative derivatives trading.
The prohibition exists to protect people from the social and economic harm caused by gambling. Islamic finance promotes risk-sharing and productive economic activity instead of zero-sum speculation.