In chess, a player is said to be "winning" when they have a significant advantage or advantages over their opponent in terms of material or positional advantage.

Chess advantages are estimated in terms of the approximate number of pawns they are worth. In modern computer evaluation a player is typically said to be winning if they have advantage(s) estimated at two pawns or greater. A player with an advantage of less than around two pawns is typically said to be not yet "winning" and merely "better."

Conversely, a player who is estimated to be at a disadvantage of two pawns or greater is said to be "losing."

A player who is "winning" is not necessarily guaranteed to win the game. They still have to "convert" their advantage into a victory, which can be much easier said than done. If they make a series of inaccuracies, a few mistakes, or even a single blunder, they can quickly go from "winning" to "drawn" or even "losing"