What is a Slow Roll in Poker?
A slow roll in poker is a deliberate action of not showing a winning hand at the showdown or pretending to think for a long time before making a call when you have the best hand and you know you are going to win. It’s considered poor etiquette and, while not illegal, is something you should avoid doing.
You have an AJ of spades on a Ks Ts 9c 5d 2s, you have a nut flush, which is the best possible hand in this situation. If your opponent moves all in and you pretend to think for a while before making a call, you are slow-rolling him since you know you have a winning hand, and there is nothing to consider before making that call.