A poker bust can mean several things. Firstly, it’s used as an adjective to refer to a worthless poker hand that hasn’t improved on later streets as the player hoped it would.
It can also be used as a verb to imply the action of losing all of one’s chips or eliminating an opponent by taking all of their chips.
An example of the first term could be: “I had high hopes for my four to a flush, but ended with a busted hand.” When it’s used as a verb, an example of busting or busting out is: “I had a bad run last night. My opponent busted me after less than an hour”.