A high roller, also referred to as a whale, is a gambler who wagers large amounts of money. The definition of a high roller varies. At Crown Casino in Australia. One who spends freely and extravagantly, as for luxuries or entertainment. 2. One who gambles rashly or for high stakes. 3. An organization, such as a large. a person who gambles or spends large sums of money Meaning, pronunciation, 'corporate jets still ferry in high rollers to the tables of Caesar's Palace'.