A person who risks large sums of money in gambling is often referred to as a high-stakes gambler. However, there are different words and phrases that can be used to describe such a person. One synonym for a high-stakes gambler is a whale. This term is commonly used in casinos to refer to someone who plays with high limits and can potentially lose or win vast sums of money. Another phrase that can be used instead of high-stakes gambler is a high roller, which is a more formal term that connotes prestige and a lavish lifestyle. Other synonyms for this term include big spender, risk taker, and high-stakes player.