[BruceZ]

In everyday parlance, it means acting weak when you are strong. In poker, it refers to checkraising (checking your hand and then raising when an opponent bets), or the much rarer play of just calling a bet and then reraising when an opponent raises. I believe the term technically applies only to these two situations rather than slowplaying in general where you wait until a future round to act strong, but someone could conceivably use the term to refer to slowplaying as well.