The term 'Gambler in Action' can be summarized as a wagerer, which is a person who takes risks by betting on an uncertain outcome. This type of person is often associated with gambling, as they are willing to risk their money in order to potentially gain a larger reward. They may also be involved in other activities such as stock trading or sports betting. The term 'wagerer' is derived from the Latin word 'WAGER' which means to pledge or promise.