WSD or W$SD in poker stands for Won Money at Showdown. It is a stat used to track how often a player wins money when all cards are shown. WSD is a very useful tool to have in your HUD when playing online poker, as it can help you gauge whether you should raise and play more aggressively to force a fold or stick with value betting against a particular player.
WSD Poker Example:
If a player has a low WSD, high chances are that they call almost everything and often go to showdowns. In contrast, if they have a very high WSD percentage, they are most likely folding too much and only going to showdowns when they have a very strong hand.